Disable automatic flushes on compositor contexts.

content/renderer/render_view_impl.cc

 // Copyright (c) 2012 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.
 
 #include "content/renderer/render_view_impl.h"
 
 #include <algorithm>
 #include <cmath>
 #include <string>
 #include <vector>
@@ skipping 1896 matching lines @@
   // code paths on Windows and Linux didn't yet have multisampling support.
   // Mac OS X essentially always behaves as though it's rendering offscreen.
   // Multisampling has a heavy cost especially on devices with relatively low
   // fill rate like most notebooks, and the Mac implementation would need to
   // be optimized to resolve directly into the IOSurface shared between the
   // GPU and browser processes. For these reasons and to avoid platform
   // disparities we explicitly disable antialiasing.
   WebKit::WebGraphicsContext3D::Attributes attributes;
   attributes.antialias = false;
   attributes.shareResources = true;
+  attributes.noAutomaticFlushes = true;
   WebGraphicsContext3D* context = CreateGraphicsContext3D(attributes);
   if (!context)
     return NULL;
 
   const CommandLine& command_line = *CommandLine::ForCurrentProcess();
   if (command_line.HasSwitch(switches::kEnableSoftwareCompositingGLAdapter)) {
       // In the absence of a software-based delegating renderer, use this
       // stopgap adapter class to present the software renderer output using a
       // 3d context.
       return new CompositorOutputSurface(routing_id(), NULL,
@@ skipping 4423 matching lines @@
 
   updating_frame_tree_ = true;
   active_frame_id_map_.clear();
 
   target_process_id_ = process_id;
   target_routing_id_ = route_id;
   CreateFrameTree(webview()->mainFrame(), frames);
 
   updating_frame_tree_ = false;
 }