Add a flag for enabling/disabling the new accelerated scrolling path

content/browser/web_contents/web_contents_impl.cc

Index: content/browser/web_contents/web_contents_impl.cc
diff --git a/content/browser/web_contents/web_contents_impl.cc b/content/browser/web_contents/web_contents_impl.cc
index 7d0e6c7deb7c979c39ec12c6dcb253603b3f75e3..265e06b4489d0d11cdd4c5502404d9ea564ee041 100644
--- a/content/browser/web_contents/web_contents_impl.cc
+++ b/content/browser/web_contents/web_contents_impl.cc
@@ -532,6 +532,14 @@ WebPreferences WebContentsImpl::GetWebkitPrefs(RenderViewHost* rvh,
   if (command_line.HasSwitch(switches::kDisableAcceleratedOverflowScroll))
     prefs.accelerated_compositing_for_overflow_scroll_enabled = false;
 
+  prefs.universal_accelerated_compositing_for_overflow_scroll_enabled = false;
+  if (command_line.HasSwitch(
+          switches::kEnableUniversalAcceleratedOverflowScroll))
+    prefs.universal_accelerated_compositing_for_overflow_scroll_enabled = true;
+  if (command_line.HasSwitch(
+          switches::kDisableUniversalAcceleratedOverflowScroll))
+    prefs.universal_accelerated_compositing_for_overflow_scroll_enabled = false;
+
   prefs.accelerated_compositing_for_scrollable_frames_enabled = false;
   if (command_line.HasSwitch(switches::kEnableAcceleratedScrollableFrames))
     prefs.accelerated_compositing_for_scrollable_frames_enabled = true;