MediaStream tests need to call WebHeap::collectGarbage

content/renderer/media/webrtc_local_audio_track_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/synchronization/waitable_event.h"
 #include "base/test/test_timeouts.h"
 #include "content/renderer/media/media_stream_audio_source.h"
 #include "content/renderer/media/mock_media_constraint_factory.h"
 #include "content/renderer/media/webrtc/webrtc_local_audio_track_adapter.h"
 #include "content/renderer/media/webrtc_audio_capturer.h"
 #include "content/renderer/media/webrtc_audio_device_impl.h"
 #include "content/renderer/media/webrtc_local_audio_track.h"
 #include "media/audio/audio_parameters.h"
 #include "media/base/audio_bus.h"
 #include "media/base/audio_capturer_source.h"
 #include "testing/gmock/include/gmock/gmock.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "third_party/WebKit/public/platform/WebMediaConstraints.h"
+#include "third_party/WebKit/public/web/WebHeap.h"
 #include "third_party/libjingle/source/talk/app/webrtc/mediastreaminterface.h"
 
 using ::testing::_;
 using ::testing::AnyNumber;
 using ::testing::AtLeast;
 using ::testing::Return;
 
 namespace content {
 
 namespace {
@@ skipping 154 matching lines @@
         audio_source);
     audio_source->SetAudioCapturer(capturer_.get());
     capturer_source_ = new MockCapturerSource(capturer_.get());
     EXPECT_CALL(*capturer_source_.get(), OnInitialize(_, capturer_.get(), -1))
         .WillOnce(Return());
     EXPECT_CALL(*capturer_source_.get(), SetAutomaticGainControl(true));
     EXPECT_CALL(*capturer_source_.get(), OnStart());
     capturer_->SetCapturerSourceForTesting(capturer_source_, params_);
   }
 
+  virtual void TearDown() OVERRIDE {
+    blink_source_.reset();

[haraken, 2014/09/09 04:51:16]

The reason we need to reset blink_source_ here is complicated.

The reset is needed to destruct capturer_source_ before destructing the
WebRtcLocalAudioTrackTest object. If we don't call the reset, the
capturer_source_ is destructed in a GC triggered after destructing the
WebRtcLocalAudioTrackTest object. This is too late because the testing system
complains that "the capturer_source_ was leaking when the
WebRtcLocalAudioTrackTest finished". Thus we need the reset.

The reason the capturer_source_ is not destructed soon is because the
WebRtcLocalAudioTrackTest object has a strong reference to the capturer_source_
as follows:

WebRtcLocalAudioTrackTest ==(part of object)==> WebMediaStreamSource
==(persistent handle)==> MediaStreamSource ==(OwnPtr)==> ExtraData ==(inherited
by)==> MediaStreamAudioSource ==(scoped_refptr)==> WebRtcAudioCapturer
==(scoped_refptr)==> MockCapturerSource.

Before oilpan, this long strong reference chain was broken promptly when the
WebRtcLocalAudioTrackTest gets destructed. On the other hand, after oilpan, the
chain is not broken until a next GC happens after the WebRtcLocalAudioTrackTest
gets destructed (if we don't call the explicit reset() in TearDown and
explicitly break the chain).

For the same reason, this CL adds a couple of reset() calls in TearDown(). (The
reset() calls in other tests are more complicated to explain why they are
needed. The chain is very long.)

+    blink::WebHeap::collectAllGarbage();
+  }
+
   media::AudioParameters params_;
   blink::WebMediaStreamSource blink_source_;
   scoped_refptr<MockCapturerSource> capturer_source_;
   scoped_refptr<WebRtcAudioCapturer> capturer_;
 };
 
 // Creates a capturer and audio track, fakes its audio thread, and
 // connect/disconnect the sink to the audio track on the fly, the sink should
 // get data callback when the track is connected to the capturer but not when
 // the track is disconnected from the capturer.
@@ skipping 325 matching lines @@
   // Stopping the new source will stop the second track.
   EXPECT_CALL(*source.get(), OnStop()).Times(1);
   capturer->Stop();
 
   // Even though this test don't use |capturer_source_| it will be stopped
   // during teardown of the test harness.
   EXPECT_CALL(*capturer_source_.get(), OnStop());
 }
 
 }  // namespace content