Polish the SystemInfoProvider template code and refactor StorageInfoProvider based on it

chrome/browser/extensions/api/system_info_storage/system_info_storage_apitest.cc

Index: chrome/browser/extensions/api/system_info_storage/system_info_storage_apitest.cc
diff --git a/chrome/browser/extensions/api/system_info_storage/system_info_storage_apitest.cc b/chrome/browser/extensions/api/system_info_storage/system_info_storage_apitest.cc
index c55d0ae3edb2866c75d556dcfc059c1ec7a4a828..9d467065b64c6b7c75ad9e932199b5b5a417ae2d 100644
--- a/chrome/browser/extensions/api/system_info_storage/system_info_storage_apitest.cc
+++ b/chrome/browser/extensions/api/system_info_storage/system_info_storage_apitest.cc
@@ -2,22 +2,62 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 #include "base/command_line.h"
+#include "base/message_loop.h"
+#include "chrome/browser/extensions/api/system_info_storage/storage_info_provider.h"
 #include "chrome/browser/extensions/extension_apitest.h"
 #include "chrome/common/chrome_switches.h"
 
 namespace extensions {
 
+using api::experimental_system_info_storage::StorageInfo;
+using api::experimental_system_info_storage::StorageUnitInfo;
+
+class MockStorageInfoProvider : public StorageInfoProvider {
+ public:
+  MockStorageInfoProvider() {}
+  virtual ~MockStorageInfoProvider() {}
+
+  virtual bool QueryInfo(StorageInfo* info) OVERRIDE {
+    info->units.clear();
+
+    linked_ptr<StorageUnitInfo> unit(new StorageUnitInfo());
+    unit->id = "0xbeaf";
+    unit->type = systeminfo::kStorageTypeUnknown;
+    unit->capacity = 4098;
+    unit->available_capacity = 1024;
+
+    info->units.push_back(unit);
+    return true;
+  }
+
+  virtual bool QueryUnitInfo(const std::string& id,
+                             StorageUnitInfo* info) OVERRIDE {
+    return false;
+  }
+};
+
 class SystemInfoStorageApiTest: public ExtensionApiTest {
  public:
   SystemInfoStorageApiTest() {}
   ~SystemInfoStorageApiTest() {}
+
   virtual void SetUpCommandLine(CommandLine* command_line) OVERRIDE {
     ExtensionApiTest::SetUpCommandLine(command_line);
     command_line->AppendSwitch(switches::kEnableExperimentalExtensionApis);
   }
+
+  virtual void SetUpInProcessBrowserTestFixture() {
+    ExtensionApiTest::SetUpInProcessBrowserTestFixture();
+    message_loop_.reset(new MessageLoop(MessageLoop::TYPE_UI));
+  }
+
+ private:
+  scoped_ptr<MessageLoop> message_loop_;
 };
 
 IN_PROC_BROWSER_TEST_F(SystemInfoStorageApiTest, Storage) {
+  StorageInfoProvider* provider = new MockStorageInfoProvider();
+  StorageInfoProvider::InitializeForTesting(provider);
   ASSERT_TRUE(RunExtensionTest("systeminfo/storage")) << message_;
 }