Fix crash in renderer initialization when media pipeline is stopped

media/renderers/renderer_impl_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 <stdint.h>
 
 #include <memory>
 #include <vector>
 
 #include "base/bind.h"
@@ skipping 132 matching lines @@
   void CreateEncryptedVideoStream() { CreateVideoStream(true); }
 
   void CreateAudioAndVideoStream() {
     CreateAudioStream();
     CreateVideoStream();
   }
 
   void InitializeWithAudio() {
     CreateAudioStream();
     SetAudioRendererInitializeExpectations(PIPELINE_OK);
+    // There is a potential race between HTMLMediaElement/WMPI shutdown and
+    // renderers being initialized which might result in DemuxerStreamProvider
+    // GetStream suddenly returning NULL (see crbug.com/668604). So we are going
+    // to check here that GetStream will be invoked exactly 3 times during
+    // RendererImpl initialization to help catch potential issues. Currently the
+    // GetStream is invoked once directly from RendererImpl::Initialize, once
+    // indirectly from RendererImpl::Initialize via HasEncryptedStream and once
+    // from RendererImpl::InitializeAudioRenderer.
+    EXPECT_CALL(*demuxer_, GetStream(DemuxerStream::AUDIO))
+        .Times(2)
+        .WillRepeatedly(Return(audio_stream_.get()));
     InitializeAndExpect(PIPELINE_OK);
   }
 
   void InitializeWithVideo() {
     CreateVideoStream();
     SetVideoRendererInitializeExpectations(PIPELINE_OK);
+    // There is a potential race between HTMLMediaElement/WMPI shutdown and
+    // renderers being initialized which might result in DemuxerStreamProvider
+    // GetStream suddenly returning NULL (see crbug.com/668604). So we are going
+    // to check here that GetStream will be invoked exactly 3 times during
+    // RendererImpl initialization to help catch potential issues. Currently the
+    // GetStream is invoked once directly from RendererImpl::Initialize, once
+    // indirectly from RendererImpl::Initialize via HasEncryptedStream and once
+    // from RendererImpl::InitializeVideoRenderer.
+    EXPECT_CALL(*demuxer_, GetStream(DemuxerStream::VIDEO))
+        .Times(2)
+        .WillRepeatedly(Return(video_stream_.get()));
     InitializeAndExpect(PIPELINE_OK);
   }
 
   void InitializeWithAudioAndVideo() {
     CreateAudioAndVideoStream();
     SetAudioRendererInitializeExpectations(PIPELINE_OK);
     SetVideoRendererInitializeExpectations(PIPELINE_OK);
     InitializeAndExpect(PIPELINE_OK);
   }
 
@@ skipping 567 matching lines @@
   EXPECT_CALL(*audio_renderer_, Flush(_)).WillOnce(RunClosure<0>());
   EXPECT_CALL(*audio_renderer_, StartPlaying()).Times(1);
   audio_stream_status_change_cb.Run(false, time0);
 
   EXPECT_CALL(*video_renderer_, Flush(_)).WillOnce(RunClosure<0>());
   EXPECT_CALL(*video_renderer_, StartPlayingFrom(_)).Times(1);
   video_stream_status_change_cb.Run(false, time0);
 }
 
 }  // namespace media