Ignore sink start attempts when no frames are present.

media/renderers/video_renderer_impl.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 "media/renderers/video_renderer_impl.h"
 
 #include <utility>
 
 #include "base/bind.h"
 #include "base/callback.h"
@@ skipping 281 matching lines @@
 
   // WARNING: Do not attempt to use |lock_| here as this may be a reentrant call
   // in response to callbacks firing above.
 
   if (sink_started_ == time_progressing_)
     return;
 
   if (time_progressing_) {
     // If only an EOS frame came in after a seek, the renderer may not have
     // received the ended event yet though we've posted it.
-    if (!rendered_end_of_stream_)
-      StartSink();
+    if (rendered_end_of_stream_)
+      return;
+
+    // If we have no frames queued, there is a pending buffering state change in
+    // flight and we should ignore the start attempt.
+    if (!algorithm_->frames_queued()) {
+      DCHECK_EQ(buffering_state_, BUFFERING_HAVE_NOTHING);
+      return;
+    }
+
+    StartSink();
   } else {
     StopSink();
 
     // Make sure we expire everything we can if we can't read anymore currently,
     // otherwise playback may hang indefinitely.  Note: There are no effective
     // frames queued at this point, otherwise FrameReady() would have canceled
     // the underflow state before reaching this point.
     if (buffering_state_ == BUFFERING_HAVE_NOTHING)
       RemoveFramesForUnderflowOrBackgroundRendering();
   }
@@ skipping 342 matching lines @@
   // the entire queue.  Note: this may cause slight inaccuracies in the number
   // of dropped frames since the frame may have been rendered before.
   if (!sink_started_ && !algorithm_->effective_frames_queued()) {
     frames_dropped_ += algorithm_->frames_queued();
     algorithm_->Reset(
         VideoRendererAlgorithm::ResetFlag::kPreserveNextFrameEstimates);
   }
 }
 
 }  // namespace media