Replace WaitableEvents and ConditionalVariables in VideoRendererBase tests with MessageLoop.

media/filters/file_data_source_unittest.cc

 // Copyright (c) 2012 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 <string>
 
 #include "base/base_paths.h"
 #include "base/bind.h"
 #include "base/file_path.h"
 #include "base/path_service.h"
 #include "base/utf_string_conversions.h"
-#include "media/base/mock_callback.h"
 #include "media/base/mock_data_source_host.h"
+#include "media/base/test_helpers.h"
 #include "media/filters/file_data_source.h"
 
 using ::testing::NiceMock;
 using ::testing::StrictMock;
 
 namespace media {
 
 class ReadCBHandler {
  public:
   ReadCBHandler() {}
@@ skipping 67 matching lines @@
 
   EXPECT_CALL(handler, ReadCB(5));
   filter->Read(5, 10, ten_bytes, base::Bind(
       &ReadCBHandler::ReadCB, base::Unretained(&handler)));
   EXPECT_EQ('5', ten_bytes[0]);
 
   filter->Stop(NewExpectedClosure());
 }
 
 }  // namespace media