MediaStream content_unittests need to trigger a GC before tear down

content/renderer/media/webrtc_local_audio_source_provider_unittest.cc

Index: content/renderer/media/webrtc_local_audio_source_provider_unittest.cc
diff --git a/content/renderer/media/webrtc_local_audio_source_provider_unittest.cc b/content/renderer/media/webrtc_local_audio_source_provider_unittest.cc
index 6c7bb64b7bc8902726e3f137809ce72a14ea40c5..0c3b0be1d6dcdae77feadd7cafc9507322b2b337 100644
--- a/content/renderer/media/webrtc_local_audio_source_provider_unittest.cc
+++ b/content/renderer/media/webrtc_local_audio_source_provider_unittest.cc
@@ -13,6 +13,7 @@
 #include "media/base/audio_bus.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "third_party/WebKit/public/platform/WebMediaStreamTrack.h"
+#include "third_party/WebKit/public/web/WebHeap.h"
 
 namespace content {
 
@@ -50,6 +51,12 @@ class WebRtcLocalAudioSourceProviderTest : public testing::Test {
     source_provider_->OnSetFormat(source_params_);
   }
 
+  virtual void TearDown() OVERRIDE {
+    source_provider_.reset();
+    blink_track_.reset();
+    blink::WebHeap::collectAllGarbageForTesting();
+  }
+
   media::AudioParameters source_params_;
   scoped_ptr<int16[]> source_data_;
   media::AudioParameters sink_params_;