Turn off computation of the interest rect in cc in synchronized paint mode.

content/renderer/gpu/render_widget_compositor.cc

 // Copyright (c) 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.
 
 #include "content/renderer/gpu/render_widget_compositor.h"
 
 #include <limits>
 #include <string>
 
 #include "base/command_line.h"
@@ skipping 289 matching lines @@
   settings.use_partial_raster = compositor_deps_->IsPartialRasterEnabled();
   settings.enable_elastic_overscroll =
       compositor_deps_->IsElasticOverscrollEnabled();
   settings.renderer_settings.use_gpu_memory_buffer_resources =
       compositor_deps_->IsGpuMemoryBufferCompositorResourcesEnabled();
   settings.use_image_texture_targets =
       compositor_deps_->GetImageTextureTargets();
   settings.image_decode_tasks_enabled =
       compositor_deps_->AreImageDecodeTasksEnabled();
 
+  settings.blink_synchronized_painting_enabled =
+    cmd->HasSwitch(switches::kEnableBlinkSynchronizedPainting);
+
   if (cmd->HasSwitch(cc::switches::kTopControlsShowThreshold)) {
       std::string top_threshold_str =
           cmd->GetSwitchValueASCII(cc::switches::kTopControlsShowThreshold);
       double show_threshold;
       if (base::StringToDouble(top_threshold_str, &show_threshold) &&
           show_threshold >= 0.f && show_threshold <= 1.f)
         settings.top_controls_show_threshold = show_threshold;
   }
 
   if (cmd->HasSwitch(cc::switches::kTopControlsHideThreshold)) {
@@ skipping 764 matching lines @@
 #endif
   return actual;
 }
 
 void RenderWidgetCompositor::SetPaintedDeviceScaleFactor(
     float device_scale) {
   layer_tree_host_->SetPaintedDeviceScaleFactor(device_scale);
 }
 
 }  // namespace content