Ignore sink start attempts when no frames are present.

media/renderers/video_renderer_impl_unittest.cc

Index: media/renderers/video_renderer_impl_unittest.cc
diff --git a/media/renderers/video_renderer_impl_unittest.cc b/media/renderers/video_renderer_impl_unittest.cc
index 7f90a6388e2ffb6f1dbc402c3df4c5a7e6202243..5ad6e6da44c13a7b8861a8d3902bbca75961279c 100644
--- a/media/renderers/video_renderer_impl_unittest.cc
+++ b/media/renderers/video_renderer_impl_unittest.cc
@@ -337,6 +337,10 @@ class VideoRendererImplTest
       Mock::VerifyAndClearExpectations(&mock_cb_);
     }
 
+    // Simulate delayed buffering state callbacks.
+    renderer_->OnTimeStateChanged(false);
+    renderer_->OnTimeStateChanged(true);
+
     // Receiving end of stream should signal having enough.
     {
       SCOPED_TRACE("Waiting for BUFFERING_HAVE_ENOUGH");