Relanding 'Always notify the MediaPlayer of any seek' patch

LayoutTests/media/controls-restrained-media-controller.html

Index: LayoutTests/media/controls-restrained-media-controller.html
diff --git a/LayoutTests/media/controls-restrained-media-controller.html b/LayoutTests/media/controls-restrained-media-controller.html
index 739dcd205720052b5b1b7f174fa2e953dd1bcc6b..783f48a04898b5e1812777ad137568fb04e36ff8 100644
--- a/LayoutTests/media/controls-restrained-media-controller.html
+++ b/LayoutTests/media/controls-restrained-media-controller.html
@@ -13,8 +13,8 @@ video.src = findMediaFile('video', 'content/test');
 
 if (window.testRunner) {
   testRunner.waitUntilDone();
-  video.addEventListener('canplay', function() {
+  window.setTimeout(function() {

[philipj_slow, 2014/12/15 14:52:38]

Having a timeout is a recipe for future flakiness. From the failure it looks
like we're not guaranteed to have decoded and painted the first frame in the
canplay event, which seems very odd. It also seems to have failed on all bots,
so is it actually flaky? The test doesn't even explicitly set currentTime, so
how is it related to the change this CL makes?

     testRunner.notifyDone();
-  });
+  }, 100);
 }
 </script>