MediaStream content_unittests need to trigger a GC before tear down

content/renderer/media/webrtc/webrtc_media_stream_adapter_unittest.cc

 // Copyright 2014 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/memory/scoped_ptr.h"
 #include "base/message_loop/message_loop.h"
 #include "content/child/child_process.h"
 #include "content/renderer/media/media_stream.h"
 #include "content/renderer/media/media_stream_audio_source.h"
 #include "content/renderer/media/media_stream_video_source.h"
 #include "content/renderer/media/media_stream_video_track.h"
 #include "content/renderer/media/mock_media_stream_video_source.h"
 #include "content/renderer/media/webrtc/mock_peer_connection_dependency_factory.h"
 #include "content/renderer/media/webrtc/webrtc_local_audio_track_adapter.h"
 #include "content/renderer/media/webrtc/webrtc_media_stream_adapter.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "third_party/WebKit/public/platform/WebMediaStream.h"
 #include "third_party/WebKit/public/platform/WebMediaStreamSource.h"
 #include "third_party/WebKit/public/platform/WebMediaStreamTrack.h"
 #include "third_party/WebKit/public/platform/WebVector.h"
+#include "third_party/WebKit/public/web/WebHeap.h"
 
 namespace content {
 
 class WebRtcMediaStreamAdapterTest : public ::testing::Test {
  public:
   virtual void SetUp() {
     child_process_.reset(new ChildProcess());
     dependency_factory_.reset(new MockPeerConnectionDependencyFactory());
   }
 
+  virtual void TearDown() OVERRIDE {
+    adapter_.reset();
+    blink::WebHeap::collectAllGarbageForTesting();
+  }
+
   blink::WebMediaStream CreateBlinkMediaStream(bool audio, bool video) {
     blink::WebVector<blink::WebMediaStreamTrack> audio_track_vector(
         audio ? static_cast<size_t>(1) : 0);
     if (audio) {
       blink::WebMediaStreamSource audio_source;
       audio_source.initialize("audio",
                               blink::WebMediaStreamSource::TypeAudio,
                               "audio");
       audio_source.setExtraData(new MediaStreamAudioSource());
 
@@ skipping 105 matching lines @@
   EXPECT_TRUE(webrtc_stream()->GetVideoTracks().empty());
 
   native_stream->AddTrack(audio_tracks[0]);
   EXPECT_EQ(1u, webrtc_stream()->GetAudioTracks().size());
 
   native_stream->AddTrack(video_tracks[0]);
   EXPECT_EQ(1u, webrtc_stream()->GetVideoTracks().size());
 }
 
 }  // namespace content