Mac: Fix janky YouTube animations

content/browser/renderer_host/compositing_iosurface_layer_mac.h

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CONTENT_BROWSER_RENDERER_HOST_COMPOSITING_IOSURFACE_LAYER_MAC_H_
 #define CONTENT_BROWSER_RENDERER_HOST_COMPOSITING_IOSURFACE_LAYER_MAC_H_
 
 #import <Cocoa/Cocoa.h>
 
 #include "base/mac/scoped_cftyperef.h"
@@ skipping 33 matching lines @@
   void SetNeedsDisplay();
 
   // Called whenever -[CompositingIOSurfaceLayer canDrawInCGLContext] is called,
   // to determine if a new frame should be drawn.
   bool CanDraw();
 
   // Called whenever -[CompositingIOSurfaceLayer drawInCGLContext] draws a
   // frame.
   void DidDraw(bool success);
 
+  // Immediately re-draw the layer, even if the content has not changed, and
+  // ensure that the frame be acked.

[ccameron, 2014/07/22 06:40:42]

I renamed these methods to be a bit more explicit.

+  void SetNeedsDisplayAndDisplayAndAck();
+
+  // Immediately draw the layer, only if one is pending, and ensure that the
+  // frame be acked.
+  void DisplayIfNeededAndAck();
  private:
-  // Immediately draw a frame (disregarding vsync) and ensure that the frame is
-  // acknowledged.
-  void ImmediatelyForceDisplayAndAck();
 
   // Called whenever the frame provided in GotNewFrame should be acknowledged
   // (this may be because it was drawn, or it may be to unblock the
   // compositor).
   void AckPendingFrame(bool success);
 
   void TimerFired();
 
   // The client that the owning layer was created with.
   content::CompositingIOSurfaceLayerClient* const client_;
@@ skipping 39 matching lines @@
         withScaleFactor:(float)scale_factor
              withClient:(content::CompositingIOSurfaceLayerClient*)client;
 
 // Mark that the client is no longer valid and cannot be called back into. This
 // must be called before the layer is destroyed.
 - (void)resetClient;
 
 // Called when a new frame is received.
 - (void)gotNewFrame;
 
+// Force a draw immediately (even if this means re-displaying a previously
+// displayed frame).
+- (void)setNeedsDisplayAndDisplayAndAck;
+
+// Force a draw immediately, but only if one was requested.
+- (void)displayIfNeededAndAck;
+
 @end
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_COMPOSITING_IOSURFACE_LAYER_MAC_H_