Revert of Use a single CGLContextObj to draw and update the IOSurface

content/browser/compositor/io_surface_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_COMPOSITOR_IO_SURFACE_LAYER_MAC_H_
 #define CONTENT_BROWSER_COMPOSITOR_IO_SURFACE_LAYER_MAC_H_
 
 #import <Cocoa/Cocoa.h>
 
 #include "base/mac/scoped_cftyperef.h"
 #include "base/memory/ref_counted.h"
 #include "base/timer/timer.h"
 #include "ui/gfx/size.h"
 
 @class IOSurfaceLayer;
 
 namespace content {
 class IOSurfaceTexture;
+class IOSurfaceContext;
 
 // The interface through which the IOSurfaceLayer calls back into
 // the structrue that created it (RenderWidgetHostViewMac or
 // BrowserCompositorViewMac).
 class IOSurfaceLayerClient {
  public:
   // Used to indicate that the layer should attempt to draw immediately and
   // should (even if the draw is elided by the system), ack the frame
   // immediately.
   virtual bool IOSurfaceLayerShouldAckImmediately() const = 0;
@@ skipping 80 matching lines @@
   // acknowledging the frame after timeout of 1/6th of a second  has passed.
   base::DelayTimer<IOSurfaceLayerHelper> timer_;
 };
 
 }  // namespace content
 
 // The CoreAnimation layer for drawing accelerated content.
 @interface IOSurfaceLayer : CAOpenGLLayer {
  @private
   scoped_refptr<content::IOSurfaceTexture> iosurface_;
+  scoped_refptr<content::IOSurfaceContext> context_;
+
   scoped_ptr<content::IOSurfaceLayerHelper> helper_;
 }
 
 - (id)initWithClient:(content::IOSurfaceLayerClient*)client
      withScaleFactor:(float)scale_factor;
 
 - (bool)gotFrameWithIOSurface:(IOSurfaceID)io_surface_id
                 withPixelSize:(gfx::Size)pixel_size
               withScaleFactor:(float)scale_factor;
 
@@ skipping 20 matching lines @@
 // Force a draw immediately, but only if one was requested.
 - (void)displayIfNeededAndAck;
 
 // Mark a bracket in which new frames are being pumped in a restricted nested
 // run loop.
 - (void)beginPumpingFrames;
 - (void)endPumpingFrames;
 @end
 
 #endif  // CONTENT_BROWSER_COMPOSITOR_IO_SURFACE_LAYER_MAC_H_