Add --enable-slimming-paint command line flag

content/browser/renderer_host/render_view_host_impl.cc

Index: content/browser/renderer_host/render_view_host_impl.cc
diff --git a/content/browser/renderer_host/render_view_host_impl.cc b/content/browser/renderer_host/render_view_host_impl.cc
index ad6908c301266454a63d054ca33c08217dcc469d..c88f28643130e22cc974c7020094460c9644909b 100644
--- a/content/browser/renderer_host/render_view_host_impl.cc
+++ b/content/browser/renderer_host/render_view_host_impl.cc
@@ -415,6 +415,9 @@ WebPreferences RenderViewHostImpl::ComputeWebkitPrefs(const GURL& url) {
   prefs.touch_adjustment_enabled =
       !command_line.HasSwitch(switches::kDisableTouchAdjustment);
 
+  prefs.slimming_paint_enabled =
+      command_line.HasSwitch(switches::kEnableSlimmingPaint);
+
 #if defined(OS_MACOSX) || defined(OS_CHROMEOS)
   bool default_enable_scroll_animator = true;
 #else