Add playback underflow logic to media::VideoRendererImpl.

media/filters/video_renderer_impl_unittest.cc

Index: media/filters/video_renderer_impl_unittest.cc
diff --git a/media/filters/video_renderer_impl_unittest.cc b/media/filters/video_renderer_impl_unittest.cc
index efa45fb1ab52686104ea8efadb10a7d5d3d72982..56898926cc63092c376fb05694f0e5cbcd9237bc 100644
--- a/media/filters/video_renderer_impl_unittest.cc
+++ b/media/filters/video_renderer_impl_unittest.cc
@@ -421,7 +421,7 @@ TEST_F(VideoRendererImplTest, FlushWithNothingBuffered) {
 
 TEST_F(VideoRendererImplTest, EndOfStream_ClipDuration) {
   Initialize();
-  QueueFrames("0 10 20 30");
+  QueueFrames("0");
   EXPECT_CALL(mock_cb_, Display(HasTimestamp(0)));
   EXPECT_CALL(mock_cb_, BufferingStateChange(BUFFERING_HAVE_ENOUGH));
   StartPlayingFrom(0);
@@ -497,8 +497,12 @@ TEST_F(VideoRendererImplTest, StartPlayingFrom_LowDelay) {
   InitializeWithLowDelay(true);
   QueueFrames("0");
 
+  // Expect to frequently have enough/nothing due to only requiring one frame.
   EXPECT_CALL(mock_cb_, Display(HasTimestamp(0)));
-  EXPECT_CALL(mock_cb_, BufferingStateChange(BUFFERING_HAVE_ENOUGH));
+  EXPECT_CALL(mock_cb_, BufferingStateChange(BUFFERING_HAVE_ENOUGH))
+      .Times(AtLeast(1));
+  EXPECT_CALL(mock_cb_, BufferingStateChange(BUFFERING_HAVE_NOTHING))
+      .Times(AtLeast(1));
   StartPlayingFrom(0);
 
   QueueFrames("10");
@@ -547,4 +551,35 @@ TEST_F(VideoRendererImplTest, VideoDecoder_InitFailure) {
   Stop();
 }
 
+TEST_F(VideoRendererImplTest, Underflow) {
+  Initialize();
+  QueueFrames("0 10 20 30");
+  EXPECT_CALL(mock_cb_, Display(HasTimestamp(0)));
+  EXPECT_CALL(mock_cb_, BufferingStateChange(BUFFERING_HAVE_ENOUGH));
+  StartPlayingFrom(0);
+
+  // Frames should be dropped and we should signal having nothing.
+  {
+    SCOPED_TRACE("Waiting for BUFFERING_HAVE_NOTHING");
+    WaitableMessageLoopEvent event;
+    EXPECT_CALL(mock_cb_, BufferingStateChange(BUFFERING_HAVE_NOTHING))
+        .WillOnce(RunClosure(event.GetClosure()));
+    AdvanceTimeInMs(100);
+    event.RunAndWait();
+  }
+
+  // Receiving end of stream should signal having enough.
+  {
+    SCOPED_TRACE("Waiting for BUFFERING_HAVE_ENOUGH");
+    WaitableMessageLoopEvent event;
+    EXPECT_CALL(mock_cb_, BufferingStateChange(BUFFERING_HAVE_ENOUGH))
+        .WillOnce(RunClosure(event.GetClosure()));
+    SatisfyPendingReadWithEndOfStream();
+    event.RunAndWait();
+  }
+
+  WaitForEnded();
+  Shutdown();
+}
+
 }  // namespace media