Eliminate MediaPlayer & MediaPlayerClient abstractions(ground work for eliminating rate APIs)

content/renderer/media/webmediaplayer_impl.cc

Index: content/renderer/media/webmediaplayer_impl.cc
diff --git a/content/renderer/media/webmediaplayer_impl.cc b/content/renderer/media/webmediaplayer_impl.cc
index 6aa009a18f401e9d954f6649fbfd9c073f53c634..26ee409d4c6c97103c87f7b8ce530012ce409b9b 100644
--- a/content/renderer/media/webmediaplayer_impl.cc
+++ b/content/renderer/media/webmediaplayer_impl.cc
@@ -402,6 +402,9 @@ void WebMediaPlayerImpl::seek(double seconds) {
 void WebMediaPlayerImpl::setRate(double rate) {
   DCHECK(main_loop_->BelongsToCurrentThread());
 
+  if (rate == playback_rate_)

[acolwell GONE FROM CHROMIUM, 2014/06/02 22:37:02]

Do we really need this? Shouldn't the caller in Blink simply not make the call
to setRate() if rate is identical?

+    return;
+
   // TODO(kylep): Remove when support for negatives is added. Also, modify the
   // following checks so rewind uses reasonable values also.
   if (rate < 0.0)