Tie multibuffers to URLs

media/blink/multibuffer_data_source_unittest.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/bind.h"
 #include "base/message_loop/message_loop.h"
 #include "base/run_loop.h"
 #include "media/base/media_log.h"
 #include "media/base/mock_filters.h"
 #include "media/base/test_helpers.h"
 #include "media/blink/buffered_data_source.h"
 #include "media/blink/mock_webframeclient.h"
 #include "media/blink/mock_weburlloader.h"
+#include "media/blink/multibuffer_data_source.h"
+#include "media/blink/multibuffer_reader.h"
 #include "media/blink/test_response_generator.h"
 #include "third_party/WebKit/public/platform/WebURLResponse.h"
 #include "third_party/WebKit/public/web/WebLocalFrame.h"
 #include "third_party/WebKit/public/web/WebView.h"
 
 using ::testing::_;
 using ::testing::Assign;
 using ::testing::DoAll;
 using ::testing::Invoke;
 using ::testing::InvokeWithoutArgs;
 using ::testing::InSequence;
 using ::testing::NiceMock;
 using ::testing::StrictMock;
 
 using blink::WebLocalFrame;
 using blink::WebString;
 using blink::WebURLLoader;
 using blink::WebURLResponse;
 using blink::WebView;
 
 namespace media {
 
+class MockResourceMultiBuffer;
+
+class MockMultiBufferDataProvider : public ResourceMultiBufferDataProvider {
+ public:
+  MockMultiBufferDataProvider(MultiBuffer::BlockId pos,
+                              MockResourceMultiBuffer* multibuffer);
+  ~MockMultiBufferDataProvider();
+  void ForgetMockMultiBuffer() { mock_multibuffer_ = nullptr; }
+  void Start() override {
+    // Create a mock active loader.
+    // Keep track of active loading state via loadAsynchronously() and cancel().
+    NiceMock<MockWebURLLoader>* url_loader = new NiceMock<MockWebURLLoader>();
+    ON_CALL(*url_loader, cancel())
+        .WillByDefault(Assign(&loading_, false));
+    loading_ = true;
+    active_loader_.reset(
+        new ActiveLoader(scoped_ptr<WebURLLoader>(url_loader)));
+    if (!on_start_.is_null()) {
+      on_start_.Run();
+    }
+  }
+
+  bool loading() const { return loading_; }
+  void RunOnStart(base::Closure cb) {
+    on_start_ = cb;
+  }
+
+ private:
+  MockResourceMultiBuffer* mock_multibuffer_;
+  bool loading_;
+  base::Closure on_start_;
+};
+
+class MockResourceMultiBuffer : public ResourceMultiBuffer {
+ public:
+  explicit MockResourceMultiBuffer(blink::WebFrame* frame)
+      : ResourceMultiBuffer(frame) {
+  }
+  ~MockResourceMultiBuffer() override {
+    for (auto i : data_providers_)
+      i->ForgetMockMultiBuffer();
+  }
+  MultiBuffer::DataProvider* CreateWriter(const BlockId& pos) override {
+    MockMultiBufferDataProvider* ret =
+        new MockMultiBufferDataProvider(pos, this);
+    data_providers_.insert(ret);
+    ret->Start();
+    return ret;
+  }
+  void Unregister(MockMultiBufferDataProvider* provider) {
+    data_providers_.erase(provider);
+  }
+
+  MockMultiBufferDataProvider* GetProvider() {
+    EXPECT_EQ(data_providers_.size(), 1U);
+    if (data_providers_.size() != 1) return nullptr;
+    return *data_providers_.begin();
+  }
+  MockMultiBufferDataProvider* GetProvider_allownull() {
+    EXPECT_LE(data_providers_.size(), 1U);
+    if (data_providers_.size() != 1U) return nullptr;
+    return *data_providers_.begin();
+  }
+  bool HasProvider() const {
+    return data_providers_.size() == 1U;
+  }
+  bool loading() {
+    if (data_providers_.empty()) return false;
+    return GetProvider()->loading();
+  }
+ private:
+  std::set<MockMultiBufferDataProvider*> data_providers_;
+};
+
+MockMultiBufferDataProvider::MockMultiBufferDataProvider(
+    MultiBuffer::BlockId pos,
+    MockResourceMultiBuffer* multibuffer)
+    : ResourceMultiBufferDataProvider(pos, multibuffer),
+      mock_multibuffer_(multibuffer),
+      loading_(false) {
+}
+
+MockMultiBufferDataProvider::~MockMultiBufferDataProvider() {
+  if (mock_multibuffer_)
+    mock_multibuffer_->Unregister(this);
+}
+
 class MockBufferedDataSourceHost : public BufferedDataSourceHost {
  public:
   MockBufferedDataSourceHost() {}
   virtual ~MockBufferedDataSourceHost() {}
 
   MOCK_METHOD1(SetTotalBytes, void(int64 total_bytes));
   MOCK_METHOD2(AddBufferedByteRange, void(int64 start, int64 end));
 
  private:
   DISALLOW_COPY_AND_ASSIGN(MockBufferedDataSourceHost);
 };
 
-// Overrides CreateResourceLoader() to permit injecting a MockWebURLLoader.
-// Also keeps track of whether said MockWebURLLoader is actively loading.
-class MockBufferedDataSource : public BufferedDataSource {
+class MockMultibufferDataSource : public MultibufferDataSource {
  public:
-  MockBufferedDataSource(
+  MockMultibufferDataSource(
       const GURL& url,
       const scoped_refptr<base::SingleThreadTaskRunner>& task_runner,
+      ResourceMultiBuffer* multibuffer,
       WebLocalFrame* frame,
       BufferedDataSourceHost* host)
-      : BufferedDataSource(url,
-                           BufferedResourceLoader::kUnspecified,
-                           task_runner,
-                           frame,
-                           new media::MediaLog(),
-                           host,
-                           base::Bind(&MockBufferedDataSource::set_downloading,
-                                      base::Unretained(this))),
-        downloading_(false),
-        loading_(false) {}
-  virtual ~MockBufferedDataSource() {}
+      : MultibufferDataSource(url,
+                              UrlData::kUnspecified,
+                              task_runner,
+                              multibuffer,
+                              frame,
+                              new media::MediaLog(),
+                              host,
+                              base::Bind(
+                                  &MockMultibufferDataSource::set_downloading,
+                                  base::Unretained(this))),
+        downloading_(false) {}
 
-  MOCK_METHOD2(CreateResourceLoader, BufferedResourceLoader*(int64, int64));
-  BufferedResourceLoader* CreateMockResourceLoader(int64 first_byte_position,
-                                                   int64 last_byte_position) {
-    CHECK(!loading_) << "Previous resource load wasn't cancelled";
-
-    BufferedResourceLoader* loader =
-        BufferedDataSource::CreateResourceLoader(first_byte_position,
-                                                 last_byte_position);
-
-    // Keep track of active loading state via loadAsynchronously() and cancel().
-    NiceMock<MockWebURLLoader>* url_loader = new NiceMock<MockWebURLLoader>();
-    ON_CALL(*url_loader, loadAsynchronously(_, _))
-        .WillByDefault(Assign(&loading_, true));
-    ON_CALL(*url_loader, cancel())
-        .WillByDefault(Assign(&loading_, false));
-
-    // |test_loader_| will be used when Start() is called.
-    loader->test_loader_ = scoped_ptr<WebURLLoader>(url_loader);
-    return loader;
+  bool downloading() { return downloading_; }
+  void set_downloading(bool downloading) {
+    downloading_ = downloading;
   }
-
-  bool loading() { return loading_; }
-  void set_loading(bool loading) { loading_ = loading; }
-  bool downloading() { return downloading_; }
-  void set_downloading(bool downloading) { downloading_ = downloading; }
+  bool range_supported() { return url_data_->range_supported(); }
 
  private:
   // Whether the resource is downloading or deferred.
   bool downloading_;
 
   // Whether the resource load has starting loading but yet to been cancelled.
   bool loading_;
 
-  DISALLOW_COPY_AND_ASSIGN(MockBufferedDataSource);
+  DISALLOW_COPY_AND_ASSIGN(MockMultibufferDataSource);
 };
 
 static const int64 kFileSize = 5000000;
-static const int64 kFarReadPosition = 4000000;
-static const int kDataSize = 1024;
+static const int64 kFarReadPosition = 3997696;
+static const int kDataSize = 32 << 10;
 
 static const char kHttpUrl[] = "http://localhost/foo.webm";
 static const char kFileUrl[] = "file:///tmp/bar.webm";
 static const char kHttpDifferentPathUrl[] = "http://localhost/bar.webm";
 static const char kHttpDifferentOriginUrl[] = "http://127.0.0.1/foo.webm";
 
-class BufferedDataSourceTest : public testing::Test {
+class MultibufferDataSourceTest : public testing::Test {
  public:
-  BufferedDataSourceTest()
+  MultibufferDataSourceTest()
       : view_(WebView::create(NULL)),
         frame_(
             WebLocalFrame::create(blink::WebTreeScopeType::Document, &client_)),
-        preload_(BufferedDataSource::AUTO) {
+        preload_(MultibufferDataSource::AUTO),
+        resource_multibuffer_(frame_) {
     view_->setMainFrame(frame_);
   }
 
-  virtual ~BufferedDataSourceTest() {
+  virtual ~MultibufferDataSourceTest() {
     view_->close();
     frame_->close();
   }
 
   MOCK_METHOD1(OnInitialize, void(bool));
 
   void Initialize(const char* url, bool expected) {
     GURL gurl(url);
     data_source_.reset(
-        new MockBufferedDataSource(gurl,
+        new MockMultibufferDataSource(gurl,
                                    message_loop_.task_runner(),
+                                   &resource_multibuffer_,
                                    view_->mainFrame()->toWebLocalFrame(),
                                    &host_));
     data_source_->SetPreload(preload_);
 
     response_generator_.reset(new TestResponseGenerator(gurl, kFileSize));
-    ExpectCreateResourceLoader();
     EXPECT_CALL(*this, OnInitialize(expected));
-    data_source_->Initialize(base::Bind(&BufferedDataSourceTest::OnInitialize,
-                                        base::Unretained(this)));
+    data_source_->Initialize(
+        base::Bind(&MultibufferDataSourceTest::OnInitialize,
+                   base::Unretained(this)));
     message_loop_.RunUntilIdle();
 
-    bool is_http = gurl.SchemeIsHTTPOrHTTPS();
-    EXPECT_EQ(data_source_->downloading(), is_http);
+    // Always loading after initialize.
+    EXPECT_EQ(data_source_->downloading(), true);
   }
 
   // Helper to initialize tests with a valid 200 response.
   void InitializeWith200Response() {
     Initialize(kHttpUrl, true);
 
     EXPECT_CALL(host_, SetTotalBytes(response_generator_->content_length()));
     Respond(response_generator_->Generate200());
+
+    EXPECT_CALL(host_, AddBufferedByteRange(0, kDataSize));
+    ReceiveData(kDataSize);
   }
 
   // Helper to initialize tests with a valid 206 response.
   void InitializeWith206Response() {
     Initialize(kHttpUrl, true);
 
     EXPECT_CALL(host_, SetTotalBytes(response_generator_->content_length()));
     Respond(response_generator_->Generate206(0));
+    EXPECT_CALL(host_, AddBufferedByteRange(0, kDataSize));
+    ReceiveData(kDataSize);
   }
 
   // Helper to initialize tests with a valid file:// response.
   void InitializeWithFileResponse() {
     Initialize(kFileUrl, true);
 
     EXPECT_CALL(host_, SetTotalBytes(kFileSize));
     EXPECT_CALL(host_, AddBufferedByteRange(0, kFileSize));
     Respond(response_generator_->GenerateFileResponse(0));
+
+    ReceiveData(kDataSize);
   }
 
   // Stops any active loaders and shuts down the data source.
   //
   // This typically happens when the page is closed and for our purposes is
   // appropriate to do when tearing down a test.
   void Stop() {
-    if (data_source_->loading()) {
-      loader()->didFail(url_loader(), response_generator_->GenerateError());
+    if (loading()) {
+      data_provider()->didFail(
+          url_loader(), response_generator_->GenerateError());
       message_loop_.RunUntilIdle();
     }
 
     data_source_->Stop();
     message_loop_.RunUntilIdle();
   }
 
-  void ExpectCreateResourceLoader() {
-    EXPECT_CALL(*data_source_, CreateResourceLoader(_, _))
-        .WillOnce(Invoke(data_source_.get(),
-                         &MockBufferedDataSource::CreateMockResourceLoader));
-    message_loop_.RunUntilIdle();
-  }
-
   void Respond(const WebURLResponse& response) {
-    loader()->didReceiveResponse(url_loader(), response);
+    EXPECT_TRUE(url_loader());
+    if (!active_loader()) return;
+    data_provider()->didReceiveResponse(url_loader(), response);
     message_loop_.RunUntilIdle();
   }
 
   void ReceiveData(int size) {
+    EXPECT_TRUE(url_loader());
+    if (!url_loader()) return;
     scoped_ptr<char[]> data(new char[size]);
     memset(data.get(), 0xA5, size);  // Arbitrary non-zero value.
 
-    loader()->didReceiveData(url_loader(), data.get(), size, size);
+    data_provider()->didReceiveData(url_loader(), data.get(), size, size);
     message_loop_.RunUntilIdle();
   }
 
   void FinishLoading() {
-    data_source_->set_loading(false);
-    loader()->didFinishLoading(url_loader(), 0, -1);
+    EXPECT_TRUE(url_loader());
+    if (!url_loader()) return;
+    data_provider()->didFinishLoading(url_loader(), 0, -1);
     message_loop_.RunUntilIdle();
   }
 
+  void Restart() {
+    EXPECT_TRUE(data_provider());
+    EXPECT_FALSE(active_loader_allownull());
+    if (!data_provider()) return;
+    data_provider()->Start();
+  }
+
   MOCK_METHOD1(ReadCallback, void(int size));
 
-  void ReadAt(int64 position) {
-    data_source_->Read(position, kDataSize, buffer_,
-                       base::Bind(&BufferedDataSourceTest::ReadCallback,
+  void ReadAt(int64 position, int64 howmuch=kDataSize) {
+    data_source_->Read(position, howmuch, buffer_,
+                       base::Bind(&MultibufferDataSourceTest::ReadCallback,
                                   base::Unretained(this)));
     message_loop_.RunUntilIdle();
   }
 
   void ExecuteMixedResponseSuccessTest(const WebURLResponse& response1,
                                        const WebURLResponse& response2) {
     EXPECT_CALL(host_, SetTotalBytes(kFileSize));
-    EXPECT_CALL(host_, AddBufferedByteRange(kDataSize, kDataSize * 2 - 1));
-    EXPECT_CALL(host_, AddBufferedByteRange(0, kDataSize - 1));
+    EXPECT_CALL(host_, AddBufferedByteRange(0, kDataSize * 2));
+    EXPECT_CALL(host_, AddBufferedByteRange(0, kDataSize));
     EXPECT_CALL(*this, ReadCallback(kDataSize)).Times(2);
 
     Respond(response1);
+    ReceiveData(kDataSize);
     ReadAt(0);
-    ReceiveData(kDataSize);
-    EXPECT_TRUE(data_source_->loading());
+    EXPECT_TRUE(loading());
 
-    ExpectCreateResourceLoader();
     FinishLoading();
+    Restart();
     ReadAt(kDataSize);
     Respond(response2);
     ReceiveData(kDataSize);
     FinishLoading();
     Stop();
   }
 
   void ExecuteMixedResponseFailureTest(const WebURLResponse& response1,
                                        const WebURLResponse& response2) {
     EXPECT_CALL(host_, SetTotalBytes(kFileSize));
-    EXPECT_CALL(host_, AddBufferedByteRange(0, kDataSize - 1));
+    EXPECT_CALL(host_, AddBufferedByteRange(0, kDataSize));
     EXPECT_CALL(*this, ReadCallback(kDataSize));
     EXPECT_CALL(*this, ReadCallback(media::DataSource::kReadError));
 
     Respond(response1);
+    ReceiveData(kDataSize);
     ReadAt(0);
-    ReceiveData(kDataSize);
-    EXPECT_TRUE(data_source_->loading());
+    EXPECT_TRUE(loading());
 
-    ExpectCreateResourceLoader();
     FinishLoading();
+    Restart();
     ReadAt(kDataSize);
     Respond(response2);
     Stop();
   }
 
+  void CheckCapacityDefer() {
+    EXPECT_EQ(2 << 20, preload_low());
+    EXPECT_EQ(3 << 20, preload_high());
+  }
+
+  void CheckReadThenDefer() {
+    EXPECT_EQ(0, preload_low());
+    EXPECT_EQ(0, preload_high());
+  }
+
+  void CheckNeverDefer() {
+    EXPECT_EQ(1LL << 40, preload_low());
+    EXPECT_EQ(1LL << 40, preload_high());
+  }
+
   // Accessors for private variables on |data_source_|.
-  BufferedResourceLoader* loader() {
+  MultiBufferReader* loader() {
     return data_source_->loader_.get();
   }
-  ActiveLoader* active_loader() { return loader()->active_loader_.get(); }
+
+  MockMultiBufferDataProvider* data_provider() {
+    return resource_multibuffer_.GetProvider();
+  }
+  ActiveLoader* active_loader() {
+    EXPECT_TRUE(data_provider());
+    if (!data_provider()) return nullptr;
+    return data_provider()->active_loader_.get();
+  }
+  ActiveLoader* active_loader_allownull() {
+    MockMultiBufferDataProvider* data_provider =
+      resource_multibuffer_.GetProvider_allownull();
+    if (!data_provider) return nullptr;
+    return data_provider->active_loader_.get();
+  }
   WebURLLoader* url_loader() {
-    return loader()->active_loader_->loader_.get();
+    EXPECT_TRUE(active_loader());
+    if (!active_loader()) return nullptr;
+    return active_loader()->loader_.get();
   }
 
-  BufferedDataSource::Preload preload() { return data_source_->preload_; }
-  void set_preload(BufferedDataSource::Preload preload) { preload_ = preload; }
-  BufferedResourceLoader::DeferStrategy defer_strategy() {
-    return loader()->defer_strategy_;
+  bool loading() { return resource_multibuffer_.loading(); }
+
+  MultibufferDataSource::Preload preload() { return data_source_->preload_; }
+  void set_preload(MultibufferDataSource::Preload preload) {
+    preload_ = preload;
+  }
+  int64 preload_high() {
+    CHECK(loader());
+    return loader()->preload_high(); }
+  int64 preload_low() {
+    CHECK(loader());
+    return loader()->preload_low();
   }
   int data_source_bitrate() { return data_source_->bitrate_; }
   double data_source_playback_rate() { return data_source_->playback_rate_; }
-  int loader_bitrate() { return loader()->bitrate_; }
-  double loader_playback_rate() { return loader()->playback_rate_; }
   bool is_local_source() { return data_source_->assume_fully_buffered(); }
   void set_might_be_reused_from_cache_in_future(bool value) {
-    loader()->might_be_reused_from_cache_in_future_ = value;
+    data_source_->url_data_->set_cacheable(value);
   }
 
-  scoped_ptr<MockBufferedDataSource> data_source_;
-
-  scoped_ptr<TestResponseGenerator> response_generator_;
+ protected:
   MockWebFrameClient client_;
   WebView* view_;
   WebLocalFrame* frame_;
+  MultibufferDataSource::Preload preload_;
+  MockResourceMultiBuffer resource_multibuffer_;
+
+  scoped_ptr<MockMultibufferDataSource> data_source_;
+
+  scoped_ptr<TestResponseGenerator> response_generator_;
 
   StrictMock<MockBufferedDataSourceHost> host_;
   base::MessageLoop message_loop_;
 
- private:
-  // Used for calling BufferedDataSource::Read().
-  uint8 buffer_[kDataSize];
+  // Used for calling MultibufferDataSource::Read().
+  uint8 buffer_[kDataSize * 2];
 
-  BufferedDataSource::Preload preload_;
-
-  DISALLOW_COPY_AND_ASSIGN(BufferedDataSourceTest);
+  DISALLOW_COPY_AND_ASSIGN(MultibufferDataSourceTest);
 };
 
-TEST_F(BufferedDataSourceTest, Range_Supported) {
+TEST_F(MultibufferDataSourceTest, Range_Supported) {
   InitializeWith206Response();
 
-  EXPECT_TRUE(data_source_->loading());
+  EXPECT_TRUE(loading());
   EXPECT_FALSE(data_source_->IsStreaming());
   Stop();
 }
 
-TEST_F(BufferedDataSourceTest, Range_InstanceSizeUnknown) {
+TEST_F(MultibufferDataSourceTest, Range_InstanceSizeUnknown) {
   Initialize(kHttpUrl, true);
 
   Respond(response_generator_->Generate206(
       0, TestResponseGenerator::kNoContentRangeInstanceSize));
 
-  EXPECT_TRUE(data_source_->loading());
+  EXPECT_CALL(host_, AddBufferedByteRange(0, kDataSize));
+  ReceiveData(kDataSize);
+
+  EXPECT_TRUE(loading());
   EXPECT_TRUE(data_source_->IsStreaming());
   Stop();
 }
 
-TEST_F(BufferedDataSourceTest, Range_NotFound) {
+TEST_F(MultibufferDataSourceTest, Range_NotFound) {
   Initialize(kHttpUrl, false);
   Respond(response_generator_->Generate404());
 
-  EXPECT_FALSE(data_source_->loading());
+  EXPECT_FALSE(loading());
   Stop();
 }
 
-TEST_F(BufferedDataSourceTest, Range_NotSupported) {
+TEST_F(MultibufferDataSourceTest, Range_NotSupported) {
   InitializeWith200Response();
 
-  EXPECT_TRUE(data_source_->loading());
+  EXPECT_TRUE(loading());
   EXPECT_TRUE(data_source_->IsStreaming());
   Stop();
 }
 
 // Special carve-out for Apache versions that choose to return a 200 for
 // Range:0- ("because it's more efficient" than a 206)
-TEST_F(BufferedDataSourceTest, Range_SupportedButReturned200) {
+TEST_F(MultibufferDataSourceTest, Range_SupportedButReturned200) {
   Initialize(kHttpUrl, true);
   EXPECT_CALL(host_, SetTotalBytes(response_generator_->content_length()));
   WebURLResponse response = response_generator_->Generate200();
   response.setHTTPHeaderField(WebString::fromUTF8("Accept-Ranges"),
                               WebString::fromUTF8("bytes"));
   Respond(response);
 
-  EXPECT_TRUE(data_source_->loading());
+  EXPECT_CALL(host_, AddBufferedByteRange(0, kDataSize));
+  ReceiveData(kDataSize);
+
+  EXPECT_TRUE(loading());
   EXPECT_FALSE(data_source_->IsStreaming());
   Stop();
 }
 
-TEST_F(BufferedDataSourceTest, Range_MissingContentRange) {
+TEST_F(MultibufferDataSourceTest, Range_MissingContentRange) {
   Initialize(kHttpUrl, false);
   Respond(response_generator_->Generate206(
       0, TestResponseGenerator::kNoContentRange));
 
-  EXPECT_FALSE(data_source_->loading());
+  EXPECT_FALSE(loading());
   Stop();
 }
 
-TEST_F(BufferedDataSourceTest, Range_MissingContentLength) {
+TEST_F(MultibufferDataSourceTest, Range_MissingContentLength) {
   Initialize(kHttpUrl, true);
 
   // It'll manage without a Content-Length response.
   EXPECT_CALL(host_, SetTotalBytes(response_generator_->content_length()));
   Respond(response_generator_->Generate206(
       0, TestResponseGenerator::kNoContentLength));
 
-  EXPECT_TRUE(data_source_->loading());
+  EXPECT_CALL(host_, AddBufferedByteRange(0, kDataSize));
+  ReceiveData(kDataSize);
+
+  EXPECT_TRUE(loading());
   EXPECT_FALSE(data_source_->IsStreaming());
   Stop();
 }
 
-TEST_F(BufferedDataSourceTest, Range_WrongContentRange) {
+TEST_F(MultibufferDataSourceTest, Range_WrongContentRange) {
   Initialize(kHttpUrl, false);
 
   // Now it's done and will fail.
   Respond(response_generator_->Generate206(1337));
 
-  EXPECT_FALSE(data_source_->loading());
+  EXPECT_FALSE(loading());
   Stop();
 }
 
 // Test the case where the initial response from the server indicates that
 // Range requests are supported, but a later request prove otherwise.
-TEST_F(BufferedDataSourceTest, Range_ServerLied) {
+TEST_F(MultibufferDataSourceTest, Range_ServerLied) {
   InitializeWith206Response();
 
   // Read causing a new request to be made -- we'll expect it to error.
-  ExpectCreateResourceLoader();
   ReadAt(kFarReadPosition);
 
   // Return a 200 in response to a range request.
   EXPECT_CALL(*this, ReadCallback(media::DataSource::kReadError));
   Respond(response_generator_->Generate200());
 
-  EXPECT_FALSE(data_source_->loading());
+  EXPECT_FALSE(loading());
   Stop();
 }
 
-TEST_F(BufferedDataSourceTest, Http_AbortWhileReading) {
+TEST_F(MultibufferDataSourceTest, Http_AbortWhileReading) {
   InitializeWith206Response();
 
   // Make sure there's a pending read -- we'll expect it to error.
-  ReadAt(0);
+  ReadAt(kFileSize);
 
   // Abort!!!
   EXPECT_CALL(*this, ReadCallback(media::DataSource::kReadError));
   data_source_->Abort();
   message_loop_.RunUntilIdle();
 
-  EXPECT_FALSE(data_source_->loading());
+  EXPECT_FALSE(loading());
   Stop();
 }
 
-TEST_F(BufferedDataSourceTest, File_AbortWhileReading) {
+TEST_F(MultibufferDataSourceTest, File_AbortWhileReading) {
   InitializeWithFileResponse();
 
   // Make sure there's a pending read -- we'll expect it to error.
-  ReadAt(0);
+  ReadAt(kFileSize);
 
   // Abort!!!
   EXPECT_CALL(*this, ReadCallback(media::DataSource::kReadError));
   data_source_->Abort();
   message_loop_.RunUntilIdle();
 
-  EXPECT_FALSE(data_source_->loading());
+  EXPECT_FALSE(loading());
   Stop();
 }
 
-TEST_F(BufferedDataSourceTest, Http_Retry) {
+TEST_F(MultibufferDataSourceTest, Http_Retry) {
   InitializeWith206Response();
 
   // Read to advance our position.
   EXPECT_CALL(*this, ReadCallback(kDataSize));
-  EXPECT_CALL(host_, AddBufferedByteRange(0, kDataSize - 1));
   ReadAt(0);
-  ReceiveData(kDataSize);
 
   // Issue a pending read but terminate the connection to force a retry.
   ReadAt(kDataSize);
-  ExpectCreateResourceLoader();
   FinishLoading();
+  Restart();
   Respond(response_generator_->Generate206(kDataSize));
 
   // Complete the read.
   EXPECT_CALL(*this, ReadCallback(kDataSize));
-  EXPECT_CALL(host_, AddBufferedByteRange(kDataSize, (kDataSize * 2) - 1));
+  EXPECT_CALL(host_, AddBufferedByteRange(0, kDataSize * 2));
   ReceiveData(kDataSize);
 
-  EXPECT_TRUE(data_source_->loading());
+  EXPECT_TRUE(loading());
   Stop();
 }
 
-TEST_F(BufferedDataSourceTest, Http_RetryOnError) {
+TEST_F(MultibufferDataSourceTest, Http_RetryOnError) {
   InitializeWith206Response();
 
   // Read to advance our position.
   EXPECT_CALL(*this, ReadCallback(kDataSize));
-  EXPECT_CALL(host_, AddBufferedByteRange(0, kDataSize - 1));
   ReadAt(0);
-  ReceiveData(kDataSize);
 
   // Issue a pending read but trigger an error to force a retry.
   EXPECT_CALL(*this, ReadCallback(kDataSize));
-  EXPECT_CALL(host_, AddBufferedByteRange(kDataSize, (kDataSize * 2) - 1));
+  EXPECT_CALL(host_, AddBufferedByteRange(0, kDataSize * 2));
   ReadAt(kDataSize);
   base::RunLoop run_loop;
-  EXPECT_CALL(*data_source_, CreateResourceLoader(_, _))
-      .WillOnce(
-          DoAll(InvokeWithoutArgs(&run_loop, &base::RunLoop::Quit),
-                Invoke(data_source_.get(),
-                       &MockBufferedDataSource::CreateMockResourceLoader)));
-  loader()->didFail(url_loader(), response_generator_->GenerateError());
+  data_provider()->didFail(url_loader(), response_generator_->GenerateError());
+  data_provider()->RunOnStart(run_loop.QuitClosure());
   run_loop.Run();
   Respond(response_generator_->Generate206(kDataSize));
   ReceiveData(kDataSize);
   FinishLoading();
-  EXPECT_FALSE(data_source_->loading());
+  EXPECT_FALSE(loading());
   Stop();
 }
 
-TEST_F(BufferedDataSourceTest, Http_PartialResponse) {
+TEST_F(MultibufferDataSourceTest, Http_PartialResponse) {
   Initialize(kHttpUrl, true);
   WebURLResponse response1 =
       response_generator_->GeneratePartial206(0, kDataSize - 1);
   WebURLResponse response2 =
       response_generator_->GeneratePartial206(kDataSize, kDataSize * 2 - 1);
   // The origin URL of response1 and response2 are same. So no error should
   // occur.
   ExecuteMixedResponseSuccessTest(response1, response2);
 }
 
-TEST_F(BufferedDataSourceTest,
+TEST_F(MultibufferDataSourceTest,
        Http_MixedResponse_RedirectedToDifferentPathResponse) {
   Initialize(kHttpUrl, true);
   WebURLResponse response1 =
       response_generator_->GeneratePartial206(0, kDataSize - 1);
   WebURLResponse response2 =
       response_generator_->GeneratePartial206(kDataSize, kDataSize * 2 - 1);
   response2.setURL(GURL(kHttpDifferentPathUrl));
   // The origin URL of response1 and response2 are same. So no error should
   // occur.
   ExecuteMixedResponseSuccessTest(response1, response2);
 }
 
-TEST_F(BufferedDataSourceTest,
+TEST_F(MultibufferDataSourceTest,
        Http_MixedResponse_RedirectedToDifferentOriginResponse) {
   Initialize(kHttpUrl, true);
   WebURLResponse response1 =
       response_generator_->GeneratePartial206(0, kDataSize - 1);
   WebURLResponse response2 =
       response_generator_->GeneratePartial206(kDataSize, kDataSize * 2 - 1);
   response2.setURL(GURL(kHttpDifferentOriginUrl));
   // The origin URL of response1 and response2 are different. So an error should
   // occur.
   ExecuteMixedResponseFailureTest(response1, response2);
 }
 
-TEST_F(BufferedDataSourceTest,
+TEST_F(MultibufferDataSourceTest,
        Http_MixedResponse_ServiceWorkerGeneratedResponseAndNormalResponse) {
   Initialize(kHttpUrl, true);
   WebURLResponse response1 =
       response_generator_->GeneratePartial206(0, kDataSize - 1);
   response1.setWasFetchedViaServiceWorker(true);
   WebURLResponse response2 =
       response_generator_->GeneratePartial206(kDataSize, kDataSize * 2 - 1);
   // response1 is generated in a Service Worker but response2 is from a native
   // server. So an error should occur.
   ExecuteMixedResponseFailureTest(response1, response2);
 }
 
-TEST_F(BufferedDataSourceTest,
+TEST_F(MultibufferDataSourceTest,
        Http_MixedResponse_ServiceWorkerProxiedAndSameURLResponse) {
   Initialize(kHttpUrl, true);
   WebURLResponse response1 =
       response_generator_->GeneratePartial206(0, kDataSize - 1);
   response1.setWasFetchedViaServiceWorker(true);
   response1.setOriginalURLViaServiceWorker(GURL(kHttpUrl));
   WebURLResponse response2 =
       response_generator_->GeneratePartial206(kDataSize, kDataSize * 2 - 1);
   // The origin URL of response1 and response2 are same. So no error should
   // occur.
   ExecuteMixedResponseSuccessTest(response1, response2);
 }
 
-TEST_F(BufferedDataSourceTest,
+TEST_F(MultibufferDataSourceTest,
        Http_MixedResponse_ServiceWorkerProxiedAndDifferentPathResponse) {
   Initialize(kHttpUrl, true);
   WebURLResponse response1 =
       response_generator_->GeneratePartial206(0, kDataSize - 1);
   response1.setWasFetchedViaServiceWorker(true);
   response1.setOriginalURLViaServiceWorker(GURL(kHttpDifferentPathUrl));
   WebURLResponse response2 =
       response_generator_->GeneratePartial206(kDataSize, kDataSize * 2 - 1);
   // The origin URL of response1 and response2 are same. So no error should
   // occur.
   ExecuteMixedResponseSuccessTest(response1, response2);
 }
 
-TEST_F(BufferedDataSourceTest,
+TEST_F(MultibufferDataSourceTest,
        Http_MixedResponse_ServiceWorkerProxiedAndDifferentOriginResponse) {
   Initialize(kHttpUrl, true);
   WebURLResponse response1 =
       response_generator_->GeneratePartial206(0, kDataSize - 1);
   response1.setWasFetchedViaServiceWorker(true);
   response1.setOriginalURLViaServiceWorker(GURL(kHttpDifferentOriginUrl));
   WebURLResponse response2 =
       response_generator_->GeneratePartial206(kDataSize, kDataSize * 2 - 1);
   // The origin URL of response1 and response2 are different. So an error should
   // occur.
   ExecuteMixedResponseFailureTest(response1, response2);
 }
 
-TEST_F(BufferedDataSourceTest, File_Retry) {
+TEST_F(MultibufferDataSourceTest, File_Retry) {
   InitializeWithFileResponse();
 
   // Read to advance our position.
   EXPECT_CALL(*this, ReadCallback(kDataSize));
   ReadAt(0);
-  ReceiveData(kDataSize);
 
   // Issue a pending read but terminate the connection to force a retry.
   ReadAt(kDataSize);
-  ExpectCreateResourceLoader();
   FinishLoading();
+  Restart();
   Respond(response_generator_->GenerateFileResponse(kDataSize));
 
   // Complete the read.
   EXPECT_CALL(*this, ReadCallback(kDataSize));
   ReceiveData(kDataSize);
 
-  EXPECT_TRUE(data_source_->loading());
+  EXPECT_TRUE(loading());
   Stop();
 }
 
-TEST_F(BufferedDataSourceTest, Http_TooManyRetries) {
+TEST_F(MultibufferDataSourceTest, Http_TooManyRetries) {
   InitializeWith206Response();
 
   // Make sure there's a pending read -- we'll expect it to error.
-  ReadAt(0);
+  ReadAt(kDataSize);
 
   // It'll try three times.
-  ExpectCreateResourceLoader();
   FinishLoading();
-  Respond(response_generator_->Generate206(0));
+  Restart();
+  Respond(response_generator_->Generate206(kDataSize));
 
-  ExpectCreateResourceLoader();
   FinishLoading();
-  Respond(response_generator_->Generate206(0));
+  Restart();
+  Respond(response_generator_->Generate206(kDataSize));
 
-  ExpectCreateResourceLoader();
   FinishLoading();
-  Respond(response_generator_->Generate206(0));
+  Restart();
+  Respond(response_generator_->Generate206(kDataSize));
 
   // It'll error after this.
   EXPECT_CALL(*this, ReadCallback(media::DataSource::kReadError));
   FinishLoading();
 
-  EXPECT_FALSE(data_source_->loading());
+  EXPECT_FALSE(loading());
   Stop();
 }
 
-TEST_F(BufferedDataSourceTest, File_TooManyRetries) {
+TEST_F(MultibufferDataSourceTest, File_TooManyRetries) {
   InitializeWithFileResponse();
 
   // Make sure there's a pending read -- we'll expect it to error.
-  ReadAt(0);
+  ReadAt(kDataSize);
 
   // It'll try three times.
-  ExpectCreateResourceLoader();
   FinishLoading();
+  Restart();
   Respond(response_generator_->GenerateFileResponse(0));
 
-  ExpectCreateResourceLoader();
   FinishLoading();
+  Restart();
   Respond(response_generator_->GenerateFileResponse(0));
 
-  ExpectCreateResourceLoader();
   FinishLoading();
+  Restart();
   Respond(response_generator_->GenerateFileResponse(0));
 
   // It'll error after this.
   EXPECT_CALL(*this, ReadCallback(media::DataSource::kReadError));
   FinishLoading();
 
-  EXPECT_FALSE(data_source_->loading());
+  EXPECT_FALSE(loading());
   Stop();
 }
 
-TEST_F(BufferedDataSourceTest, File_InstanceSizeUnknown) {
+TEST_F(MultibufferDataSourceTest, File_InstanceSizeUnknown) {
   Initialize(kFileUrl, false);
+
+  Respond(response_generator_->GenerateFileResponse(
+      media::DataSource::kReadError));
+  ReceiveData(kDataSize);
+
   EXPECT_FALSE(data_source_->downloading());
-
-  Respond(response_generator_->GenerateFileResponse(-1));
-
-  EXPECT_FALSE(data_source_->loading());
+  EXPECT_FALSE(loading());
   Stop();
 }
 
-TEST_F(BufferedDataSourceTest, File_Successful) {
+TEST_F(MultibufferDataSourceTest, File_Successful) {
   InitializeWithFileResponse();
 
-  EXPECT_TRUE(data_source_->loading());
+  EXPECT_TRUE(loading());
   EXPECT_FALSE(data_source_->IsStreaming());
   Stop();
 }
 
-TEST_F(BufferedDataSourceTest, StopDuringRead) {
+TEST_F(MultibufferDataSourceTest, StopDuringRead) {
   InitializeWith206Response();
 
   uint8 buffer[256];
   data_source_->Read(0, arraysize(buffer), buffer, base::Bind(
-      &BufferedDataSourceTest::ReadCallback, base::Unretained(this)));
+      &MultibufferDataSourceTest::ReadCallback, base::Unretained(this)));
 
   // The outstanding read should fail before the stop callback runs.
   {
     InSequence s;
     EXPECT_CALL(*this, ReadCallback(media::DataSource::kReadError));
     data_source_->Stop();
   }
   message_loop_.RunUntilIdle();
 }
 
-TEST_F(BufferedDataSourceTest, DefaultValues) {
+TEST_F(MultibufferDataSourceTest, DefaultValues) {
   InitializeWith206Response();
 
   // Ensure we have sane values for default loading scenario.
-  EXPECT_EQ(BufferedDataSource::AUTO, preload());
-  EXPECT_EQ(BufferedResourceLoader::kCapacityDefer, defer_strategy());
+  EXPECT_EQ(MultibufferDataSource::AUTO, preload());
+  EXPECT_EQ(2 << 20, preload_low());
+  EXPECT_EQ(3 << 20, preload_high());
 
   EXPECT_EQ(0, data_source_bitrate());
   EXPECT_EQ(0.0, data_source_playback_rate());
-  EXPECT_EQ(0, loader_bitrate());
-  EXPECT_EQ(0.0, loader_playback_rate());
-
-  EXPECT_TRUE(data_source_->loading());
-  Stop();
-}
-
-TEST_F(BufferedDataSourceTest, SetBitrate) {
+
+  EXPECT_TRUE(loading());
+  Stop();
+}
+
+TEST_F(MultibufferDataSourceTest, SetBitrate) {
   InitializeWith206Response();
 
   data_source_->SetBitrate(1234);
   message_loop_.RunUntilIdle();
   EXPECT_EQ(1234, data_source_bitrate());
-  EXPECT_EQ(1234, loader_bitrate());
 
   // Read so far ahead to cause the loader to get recreated.
-  BufferedResourceLoader* old_loader = loader();
-  ExpectCreateResourceLoader();
+  MockMultiBufferDataProvider* old_loader = data_provider();
   ReadAt(kFarReadPosition);
   Respond(response_generator_->Generate206(kFarReadPosition));
 
   // Verify loader changed but still has same bitrate.
-  EXPECT_NE(old_loader, loader());
-  EXPECT_EQ(1234, loader_bitrate());
-
-  EXPECT_TRUE(data_source_->loading());
+  EXPECT_NE(old_loader, data_provider());
+
+  EXPECT_TRUE(loading());
   EXPECT_CALL(*this, ReadCallback(media::DataSource::kReadError));
   Stop();
 }
 
-TEST_F(BufferedDataSourceTest, MediaPlaybackRateChanged) {
+TEST_F(MultibufferDataSourceTest, MediaPlaybackRateChanged) {
   InitializeWith206Response();
 
   data_source_->MediaPlaybackRateChanged(2.0);
   message_loop_.RunUntilIdle();
   EXPECT_EQ(2.0, data_source_playback_rate());
-  EXPECT_EQ(2.0, loader_playback_rate());
 
   // Read so far ahead to cause the loader to get recreated.
-  BufferedResourceLoader* old_loader = loader();
-  ExpectCreateResourceLoader();
+  MockMultiBufferDataProvider* old_loader = data_provider();
   ReadAt(kFarReadPosition);
   Respond(response_generator_->Generate206(kFarReadPosition));
 
   // Verify loader changed but still has same playback rate.
-  EXPECT_NE(old_loader, loader());
-
-  EXPECT_TRUE(data_source_->loading());
+  EXPECT_NE(old_loader, data_provider());
+
+  EXPECT_TRUE(loading());
   EXPECT_CALL(*this, ReadCallback(media::DataSource::kReadError));
   Stop();
 }
 
-TEST_F(BufferedDataSourceTest, Http_Read) {
-  InitializeWith206Response();
-
+TEST_F(MultibufferDataSourceTest, Http_Read) {
+  InitializeWith206Response();
+
+  EXPECT_CALL(*this, ReadCallback(kDataSize));
+  ReadAt(0, kDataSize * 2);
+
+  ReadAt(kDataSize, kDataSize);
+  EXPECT_CALL(*this, ReadCallback(kDataSize));
+  EXPECT_CALL(host_, AddBufferedByteRange(0, kDataSize * 2));
+  ReceiveData(kDataSize/2);
+  ReceiveData(kDataSize/2);
+
+  EXPECT_TRUE(data_source_->downloading());
+  Stop();
+}
+
+TEST_F(MultibufferDataSourceTest, Http_Read_Seek) {
+  InitializeWith206Response();
+
+  // Read a bit from the beginning.
+  EXPECT_CALL(*this, ReadCallback(kDataSize));
   ReadAt(0);
 
-  // Receive first half of the read.
-  EXPECT_CALL(host_, AddBufferedByteRange(0, (kDataSize / 2) - 1));
-  ReceiveData(kDataSize / 2);
-
-  // Receive last half of the read.
-  EXPECT_CALL(*this, ReadCallback(kDataSize));
-  EXPECT_CALL(host_, AddBufferedByteRange(0, kDataSize - 1));
-  ReceiveData(kDataSize / 2);
-
-  EXPECT_TRUE(data_source_->downloading());
-  Stop();
-}
-
-TEST_F(BufferedDataSourceTest, Http_Read_Seek) {
-  InitializeWith206Response();
-
-  // Read a bit from the beginning.
-  ReadAt(0);
-  EXPECT_CALL(*this, ReadCallback(kDataSize));
-  EXPECT_CALL(host_, AddBufferedByteRange(0, kDataSize - 1));
-  ReceiveData(kDataSize);
-
   // Simulate a seek by reading a bit beyond kDataSize.
   ReadAt(kDataSize * 2);
 
   // We receive data leading up to but not including our read.
-  EXPECT_CALL(host_, AddBufferedByteRange(0, kDataSize * 2 - 1));
+  // No notification will happen, since it's progress outside
+  // of our current range.
   ReceiveData(kDataSize);
 
   // We now receive the rest of the data for our read.
   EXPECT_CALL(*this, ReadCallback(kDataSize));
-  EXPECT_CALL(host_, AddBufferedByteRange(0, kDataSize * 3 - 1));
-  ReceiveData(kDataSize);
-
-  EXPECT_TRUE(data_source_->downloading());
-  Stop();
-}
-
-TEST_F(BufferedDataSourceTest, File_Read) {
-  InitializeWithFileResponse();
-
+  EXPECT_CALL(host_, AddBufferedByteRange(0, kDataSize * 3));
+  ReceiveData(kDataSize);
+
+  EXPECT_TRUE(data_source_->downloading());
+  Stop();
+}
+
+TEST_F(MultibufferDataSourceTest, File_Read) {
+  InitializeWithFileResponse();
+
+  EXPECT_CALL(*this, ReadCallback(kDataSize));
+  ReadAt(0, kDataSize * 2);
+
+  ReadAt(kDataSize, kDataSize);
+  EXPECT_CALL(*this, ReadCallback(kDataSize));
+  ReceiveData(kDataSize);
+
+  Stop();
+}
+
+TEST_F(MultibufferDataSourceTest, Http_FinishLoading) {
+  InitializeWith206Response();
+
+  EXPECT_TRUE(data_source_->downloading());
+  // premature didFinishLoading() will cause a retry.
+  FinishLoading();
+  EXPECT_TRUE(data_source_->downloading());
+
+  Stop();
+}
+
+TEST_F(MultibufferDataSourceTest, File_FinishLoading) {
+  InitializeWithFileResponse();
+
+  ReceiveData(kDataSize);
+
+  EXPECT_TRUE(data_source_->downloading());
+  // premature didFinishLoading() will cause a retry.
+  FinishLoading();
+  EXPECT_TRUE(data_source_->downloading());
+
+  Stop();
+}
+
+TEST_F(MultibufferDataSourceTest, LocalResource_DeferStrategy) {
+  InitializeWithFileResponse();
+
+  EXPECT_EQ(MultibufferDataSource::AUTO, preload());
+  EXPECT_TRUE(is_local_source());
+  CheckCapacityDefer();
+
+  data_source_->MediaIsPlaying();
+  CheckCapacityDefer();
+
+  data_source_->MediaIsPaused();
+  CheckCapacityDefer();
+
+  Stop();
+}
+
+TEST_F(MultibufferDataSourceTest, LocalResource_PreloadMetadata_DeferStrategy) {
+  set_preload(MultibufferDataSource::METADATA);
+  InitializeWithFileResponse();
+
+  EXPECT_EQ(MultibufferDataSource::METADATA, preload());
+  EXPECT_TRUE(is_local_source());
+  CheckReadThenDefer();
+
+  data_source_->MediaIsPlaying();
+  CheckCapacityDefer();
+
+  data_source_->MediaIsPaused();
+  CheckCapacityDefer();
+
+  Stop();
+}
+
+TEST_F(MultibufferDataSourceTest, ExternalResource_Reponse200_DeferStrategy) {
+  InitializeWith200Response();
+
+  EXPECT_EQ(MultibufferDataSource::AUTO, preload());
+  EXPECT_FALSE(is_local_source());
+  EXPECT_FALSE(data_source_->range_supported());
+  CheckCapacityDefer();
+
+  data_source_->MediaIsPlaying();
+  CheckCapacityDefer();
+
+  data_source_->MediaIsPaused();
+  CheckCapacityDefer();
+
+  Stop();
+}
+
+TEST_F(MultibufferDataSourceTest,
+       ExternalResource_Response200_PreloadMetadata_DeferStrategy) {
+  set_preload(MultibufferDataSource::METADATA);
+  InitializeWith200Response();
+
+  EXPECT_EQ(MultibufferDataSource::METADATA, preload());
+  EXPECT_FALSE(is_local_source());
+  EXPECT_FALSE(data_source_->range_supported());
+  CheckReadThenDefer();
+
+  data_source_->MediaIsPlaying();
+  CheckCapacityDefer();
+
+  data_source_->MediaIsPaused();
+  CheckCapacityDefer();
+
+  Stop();
+}
+
+TEST_F(MultibufferDataSourceTest, ExternalResource_Reponse206_DeferStrategy) {
+  InitializeWith206Response();
+
+  EXPECT_EQ(MultibufferDataSource::AUTO, preload());
+  EXPECT_FALSE(is_local_source());
+  EXPECT_TRUE(data_source_->range_supported());
+  CheckCapacityDefer();
+
+  data_source_->MediaIsPlaying();
+  CheckCapacityDefer();
+  set_might_be_reused_from_cache_in_future(true);
+  data_source_->MediaIsPaused();
+  CheckNeverDefer();
+
+  data_source_->MediaIsPlaying();
+  CheckCapacityDefer();
+
+  set_might_be_reused_from_cache_in_future(false);
+  data_source_->MediaIsPaused();
+  CheckCapacityDefer();
+
+  Stop();
+}
+
+TEST_F(MultibufferDataSourceTest,
+       ExternalResource_Response206_PreloadMetadata_DeferStrategy) {
+  set_preload(MultibufferDataSource::METADATA);
+  InitializeWith206Response();
+
+  EXPECT_EQ(MultibufferDataSource::METADATA, preload());
+  EXPECT_FALSE(is_local_source());
+  EXPECT_TRUE(data_source_->range_supported());
+  CheckReadThenDefer();
+
+  data_source_->MediaIsPlaying();
+  CheckCapacityDefer();
+
+  set_might_be_reused_from_cache_in_future(true);
+  data_source_->MediaIsPaused();
+  CheckNeverDefer();
+
+  data_source_->MediaIsPlaying();
+  CheckCapacityDefer();
+  set_might_be_reused_from_cache_in_future(false);
+  data_source_->MediaIsPaused();
+  CheckCapacityDefer();
+
+  Stop();
+}
+
+TEST_F(MultibufferDataSourceTest, ExternalResource_Response206_VerifyDefer) {
+  set_preload(MultibufferDataSource::METADATA);
+  InitializeWith206Response();
+
+  EXPECT_EQ(MultibufferDataSource::METADATA, preload());
+  EXPECT_FALSE(is_local_source());
+  EXPECT_TRUE(data_source_->range_supported());
+  CheckReadThenDefer();
+
+  // Read a bit from the beginning.
+  EXPECT_CALL(*this, ReadCallback(kDataSize));
   ReadAt(0);
 
-  // Receive first half of the read but no buffering update.
-  ReceiveData(kDataSize / 2);
-
-  // Receive last half of the read but no buffering update.
-  EXPECT_CALL(*this, ReadCallback(kDataSize));
-  ReceiveData(kDataSize / 2);
-
-  Stop();
-}
-
-TEST_F(BufferedDataSourceTest, Http_FinishLoading) {
-  InitializeWith206Response();
-
-  EXPECT_TRUE(data_source_->downloading());
-  FinishLoading();
-  EXPECT_FALSE(data_source_->downloading());
-
-  Stop();
-}
-
-TEST_F(BufferedDataSourceTest, File_FinishLoading) {
-  InitializeWithFileResponse();
-
-  EXPECT_FALSE(data_source_->downloading());
-  FinishLoading();
-  EXPECT_FALSE(data_source_->downloading());
-
-  Stop();
-}
-
-TEST_F(BufferedDataSourceTest, LocalResource_DeferStrategy) {
-  InitializeWithFileResponse();
-
-  EXPECT_EQ(BufferedDataSource::AUTO, preload());
-  EXPECT_TRUE(is_local_source());
-  EXPECT_EQ(BufferedResourceLoader::kCapacityDefer, defer_strategy());
-
-  data_source_->MediaIsPlaying();
-  EXPECT_EQ(BufferedResourceLoader::kCapacityDefer, defer_strategy());
-
-  data_source_->MediaIsPaused();
-  EXPECT_EQ(BufferedResourceLoader::kCapacityDefer, defer_strategy());
-
-  Stop();
-}
-
-TEST_F(BufferedDataSourceTest, LocalResource_PreloadMetadata_DeferStrategy) {
-  set_preload(BufferedDataSource::METADATA);
-  InitializeWithFileResponse();
-
-  EXPECT_EQ(BufferedDataSource::METADATA, preload());
-  EXPECT_TRUE(is_local_source());
-  EXPECT_EQ(BufferedResourceLoader::kReadThenDefer, defer_strategy());
-
-  data_source_->MediaIsPlaying();
-  EXPECT_EQ(BufferedResourceLoader::kCapacityDefer, defer_strategy());
-
-  data_source_->MediaIsPaused();
-  EXPECT_EQ(BufferedResourceLoader::kCapacityDefer, defer_strategy());
-
-  Stop();
-}
-
-TEST_F(BufferedDataSourceTest, ExternalResource_Reponse200_DeferStrategy) {
-  InitializeWith200Response();
-
-  EXPECT_EQ(BufferedDataSource::AUTO, preload());
-  EXPECT_FALSE(is_local_source());
-  EXPECT_FALSE(loader()->range_supported());
-  EXPECT_EQ(BufferedResourceLoader::kCapacityDefer, defer_strategy());
-
-  data_source_->MediaIsPlaying();
-  EXPECT_EQ(BufferedResourceLoader::kCapacityDefer, defer_strategy());
-
-  data_source_->MediaIsPaused();
-  EXPECT_EQ(BufferedResourceLoader::kCapacityDefer, defer_strategy());
-
-  Stop();
-}
-
-TEST_F(BufferedDataSourceTest,
-       ExternalResource_Response200_PreloadMetadata_DeferStrategy) {
-  set_preload(BufferedDataSource::METADATA);
-  InitializeWith200Response();
-
-  EXPECT_EQ(BufferedDataSource::METADATA, preload());
-  EXPECT_FALSE(is_local_source());
-  EXPECT_FALSE(loader()->range_supported());
-  EXPECT_EQ(BufferedResourceLoader::kReadThenDefer, defer_strategy());
-
-  data_source_->MediaIsPlaying();
-  EXPECT_EQ(BufferedResourceLoader::kCapacityDefer, defer_strategy());
-
-  data_source_->MediaIsPaused();
-  EXPECT_EQ(BufferedResourceLoader::kCapacityDefer, defer_strategy());
-
-  Stop();
-}
-
-TEST_F(BufferedDataSourceTest, ExternalResource_Reponse206_DeferStrategy) {
-  InitializeWith206Response();
-
-  EXPECT_EQ(BufferedDataSource::AUTO, preload());
-  EXPECT_FALSE(is_local_source());
-  EXPECT_TRUE(loader()->range_supported());
-  EXPECT_EQ(BufferedResourceLoader::kCapacityDefer, defer_strategy());
-
-  data_source_->MediaIsPlaying();
-  EXPECT_EQ(BufferedResourceLoader::kCapacityDefer, defer_strategy());
-  set_might_be_reused_from_cache_in_future(true);
-  data_source_->MediaIsPaused();
-  EXPECT_EQ(BufferedResourceLoader::kNeverDefer, defer_strategy());
-
-  data_source_->MediaIsPlaying();
-  EXPECT_EQ(BufferedResourceLoader::kCapacityDefer, defer_strategy());
-  set_might_be_reused_from_cache_in_future(false);
-  data_source_->MediaIsPaused();
-  EXPECT_EQ(BufferedResourceLoader::kCapacityDefer, defer_strategy());
-
-  Stop();
-}
-
-TEST_F(BufferedDataSourceTest,
-       ExternalResource_Response206_PreloadMetadata_DeferStrategy) {
-  set_preload(BufferedDataSource::METADATA);
-  InitializeWith206Response();
-
-  EXPECT_EQ(BufferedDataSource::METADATA, preload());
-  EXPECT_FALSE(is_local_source());
-  EXPECT_TRUE(loader()->range_supported());
-  EXPECT_EQ(BufferedResourceLoader::kReadThenDefer, defer_strategy());
-
-  data_source_->MediaIsPlaying();
-  EXPECT_EQ(BufferedResourceLoader::kCapacityDefer, defer_strategy());
-  set_might_be_reused_from_cache_in_future(true);
-  data_source_->MediaIsPaused();
-  EXPECT_EQ(BufferedResourceLoader::kNeverDefer, defer_strategy());
-
-  data_source_->MediaIsPlaying();
-  EXPECT_EQ(BufferedResourceLoader::kCapacityDefer, defer_strategy());
-  set_might_be_reused_from_cache_in_future(false);
-  data_source_->MediaIsPaused();
-  EXPECT_EQ(BufferedResourceLoader::kCapacityDefer, defer_strategy());
-
-  Stop();
-}
-
-TEST_F(BufferedDataSourceTest, ExternalResource_Response206_VerifyDefer) {
-  set_preload(BufferedDataSource::METADATA);
-  InitializeWith206Response();
-
-  EXPECT_EQ(BufferedDataSource::METADATA, preload());
-  EXPECT_FALSE(is_local_source());
-  EXPECT_TRUE(loader()->range_supported());
-  EXPECT_EQ(BufferedResourceLoader::kReadThenDefer, defer_strategy());
-
-  // Read a bit from the beginning.
-  ReadAt(0);
-  EXPECT_CALL(*this, ReadCallback(kDataSize));
-  EXPECT_CALL(host_, AddBufferedByteRange(0, kDataSize - 1));
-  ReceiveData(kDataSize);
-
   ASSERT_TRUE(active_loader());
   EXPECT_TRUE(active_loader()->deferred());
 }
 
-TEST_F(BufferedDataSourceTest, ExternalResource_Response206_CancelAfterDefer) {
-  set_preload(BufferedDataSource::METADATA);
-  InitializeWith206Response();
-
-  EXPECT_EQ(BufferedDataSource::METADATA, preload());
-  EXPECT_FALSE(is_local_source());
-  EXPECT_TRUE(loader()->range_supported());
-  EXPECT_EQ(BufferedResourceLoader::kReadThenDefer, defer_strategy());
+TEST_F(MultibufferDataSourceTest,
+       ExternalResource_Response206_CancelAfterDefer) {
+  set_preload(MultibufferDataSource::METADATA);
+  InitializeWith206Response();
+
+  EXPECT_EQ(MultibufferDataSource::METADATA, preload());
+  EXPECT_FALSE(is_local_source());
+
+  EXPECT_TRUE(data_source_->range_supported());
+  CheckReadThenDefer();
+
+  ReadAt(kDataSize);
 
   data_source_->OnBufferingHaveEnough();
-
   ASSERT_TRUE(active_loader());
 
-  // Read a bit from the beginning.
-  ReadAt(0);
-  EXPECT_CALL(*this, ReadCallback(kDataSize));
-  EXPECT_CALL(host_, AddBufferedByteRange(0, kDataSize - 1));
-  ReceiveData(kDataSize);
-
-  EXPECT_FALSE(active_loader());
+  EXPECT_CALL(*this, ReadCallback(kDataSize));
+  EXPECT_CALL(host_, AddBufferedByteRange(0, kDataSize*2));
+  ReceiveData(kDataSize);
+
+  EXPECT_FALSE(active_loader_allownull());
 }
 
 }  // namespace media