Always notify the MediaPlayer of any seek.

LayoutTests/media/media-controller-effective-playback-rate.html

Index: LayoutTests/media/media-controller-effective-playback-rate.html
diff --git a/LayoutTests/media/media-controller-effective-playback-rate.html b/LayoutTests/media/media-controller-effective-playback-rate.html
index e0d28631db9727e37d01066e75ea2a994524a62c..7e06f7496b8b66c3c0e50b230b46eecdfeb2d5dd 100644
--- a/LayoutTests/media/media-controller-effective-playback-rate.html
+++ b/LayoutTests/media/media-controller-effective-playback-rate.html
@@ -13,7 +13,7 @@
                 // Set the rate on the media element so playback won't move forward.
                 video.playbackRate = 0;
 
-                waitForEvent("canplay",canplay);
+                waitForEventOnce("canplay",canplay);

[acolwell GONE FROM CHROMIUM, 2014/06/17 21:52:36]

This change and the other one like it is needed because this test assumes that
canplay will only fire once. Part of the media controller's "bringing the
element up to speed" algorithm issues a seek on the element in response to
play(). Now that the media engine is being notified of all seeks, a readyState
transition to HAVE_METADATA can occur which opens up the possibility for another
"canplay" event to fire.

This change simply changes to test to reflect the original intent which was "on
the first canplay event call canplay".

             };
 
             var canplay = function()