Add flag to disable impl-side painting

content/browser/web_contents/web_contents_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/browser/web_contents/web_contents_impl.h"
 
 #include <utility>
 
 #include "base/command_line.h"
 #include "base/metrics/histogram.h"
@@ skipping 648 matching lines @@
 
   prefs.gesture_tap_highlight_enabled = command_line.HasSwitch(
       switches::kEnableGestureTapHighlight);
 
   prefs.number_of_cpu_cores = base::SysInfo::NumberOfProcessors();
 
   prefs.viewport_enabled = command_line.HasSwitch(switches::kEnableViewport);
 
   prefs.deferred_image_decoding_enabled =
       command_line.HasSwitch(switches::kEnableDeferredImageDecoding) ||
-      command_line.HasSwitch(cc::switches::kEnableImplSidePainting);
+      cc::switches::IsImplSidePaintingEnabled();
 
   GetContentClient()->browser()->OverrideWebkitPrefs(rvh, url, &prefs);
 
   // Disable compositing in guests until we have compositing path implemented
   // for guests.
   bool guest_compositing_enabled = command_line.HasSwitch(
       switches::kEnableBrowserPluginCompositing);
   if (rvh->GetProcess()->IsGuest() && !guest_compositing_enabled) {
     prefs.force_compositing_mode = false;
     prefs.accelerated_compositing_enabled = false;
@@ skipping 2863 matching lines @@
 
 BrowserPluginGuest* WebContentsImpl::GetBrowserPluginGuest() const {
   return browser_plugin_guest_.get();
 }
 
 BrowserPluginEmbedder* WebContentsImpl::GetBrowserPluginEmbedder() const {
   return browser_plugin_embedder_.get();
 }
 
 }  // namespace content