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

content/renderer/render_view_impl.cc

Index: content/renderer/render_view_impl.cc
diff --git a/content/renderer/render_view_impl.cc b/content/renderer/render_view_impl.cc
index 18ac4b3e87968bab0bf0a865f9bddd2dfc6fed1b..6a47c7dff9957553ad779d737041831881340e29 100644
--- a/content/renderer/render_view_impl.cc
+++ b/content/renderer/render_view_impl.cc
@@ -639,6 +639,20 @@ static bool ShouldUseCompositedScrollingForFrames(
   return DeviceScaleEnsuresTextQuality(device_scale_factor);
 }
 
+static bool ShouldUseUniversalAcceleratedCompositingForOverflowScroll() {
+  const CommandLine& command_line = *CommandLine::ForCurrentProcess();
+
+  if (command_line.HasSwitch(
+          switches::kDisableUniversalAcceleratedOverflowScroll))
+    return false;
+
+  if (command_line.HasSwitch(
+          switches::kEnableUniversalAcceleratedOverflowScroll))
+    return true;
+
+  return false;
+}
+
 static bool ShouldUseTransitionCompositing(float device_scale_factor) {
   const CommandLine& command_line = *CommandLine::ForCurrentProcess();
 
@@ -928,6 +942,8 @@ void RenderViewImpl::Initialize(RenderViewImplParams* params) {
       ShouldUseFixedPositionCompositing(device_scale_factor_));
   webview()->settings()->setAcceleratedCompositingForOverflowScrollEnabled(
       ShouldUseAcceleratedCompositingForOverflowScroll(device_scale_factor_));
+  webview()->settings()->setCompositorDrivenAcceleratedScrollingEnabled(
+      ShouldUseUniversalAcceleratedCompositingForOverflowScroll());
   webview()->settings()->setAcceleratedCompositingForTransitionEnabled(
       ShouldUseTransitionCompositing(device_scale_factor_));
   webview()->settings()->setAcceleratedCompositingForFixedRootBackgroundEnabled(