Reapply "Add a switch to enable composited scrolling for frames and enable it on Android"

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 466 matching lines @@
   prefs.show_composited_layer_borders =
       command_line.HasSwitch(switches::kShowCompositedLayerBorders);
   prefs.show_composited_layer_tree =
       command_line.HasSwitch(switches::kShowCompositedLayerTree);
   prefs.show_fps_counter =
       command_line.HasSwitch(switches::kShowFPSCounter);
   prefs.accelerated_compositing_for_overflow_scroll_enabled =
       command_line.HasSwitch(switches::kEnableAcceleratedOverflowScroll);
   prefs.accelerated_compositing_for_scrollable_frames_enabled =
       command_line.HasSwitch(switches::kEnableAcceleratedScrollableFrames);
+  prefs.composited_scrolling_for_frames_enabled =
+      command_line.HasSwitch(switches::kEnableCompositedScrollingForFrames);
   prefs.show_paint_rects =
       command_line.HasSwitch(switches::kShowPaintRects);
   prefs.render_vsync_enabled =
       !command_line.HasSwitch(switches::kDisableGpuVsync);
   prefs.accelerated_compositing_enabled =
       GpuProcessHost::gpu_enabled() &&
       !command_line.HasSwitch(switches::kDisableAcceleratedCompositing);
   prefs.force_compositing_mode =
       command_line.HasSwitch(switches::kForceCompositingMode) &&
       !command_line.HasSwitch(switches::kDisableForceCompositingMode);
@@ skipping 2889 matching lines @@
 
 BrowserPluginGuest* WebContentsImpl::GetBrowserPluginGuest() {
   return browser_plugin_guest_.get();
 }
 
 BrowserPluginEmbedder* WebContentsImpl::GetBrowserPluginEmbedder() {
   return browser_plugin_embedder_.get();
 }
 
 }  // namespace content