Add enable-accelerated-compositing-for-overflow-scroll switch.

This is to turn on https://bugs.webkit.org/show_bug.cgi?id=94743.

BUG=None

Review URL: https://chromiumcodereview.appspot.com/10918079

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@157123 0039d316-1c4b-4281-b951-d872f2087c98

6 files changed, 16 insertions, 0 deletions

diff --git a/content/browser/web_contents/web_contents_impl.cc b/content/browser/web_contents/web_contents_impl.cc
index 1bd9332..54a5e17 100644
--- a/content/browser/web_contents/web_contents_impl.cc
+++ b/content/browser/web_contents/web_contents_impl.cc
@@ -490,6 +490,9 @@ WebPreferences WebContentsImpl::GetWebkitPrefs(RenderViewHost* rvh,
       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::kEnableAcceleratedCompositingForOverflowScroll);
   prefs.show_paint_rects =
       command_line.HasSwitch(switches::kShowPaintRects);
   prefs.render_vsync_enabled =
diff --git a/content/common/view_messages.h b/content/common/view_messages.h
index 422776d..3596609 100644
--- a/content/common/view_messages.h
+++ b/content/common/view_messages.h
@@ -187,6 +187,7 @@ IPC_STRUCT_TRAITS_BEGIN(webkit_glue::WebPreferences)
   IPC_STRUCT_TRAITS_MEMBER(show_composited_layer_borders)
   IPC_STRUCT_TRAITS_MEMBER(show_composited_layer_tree)
   IPC_STRUCT_TRAITS_MEMBER(show_fps_counter)
+  IPC_STRUCT_TRAITS_MEMBER(accelerated_compositing_for_overflow_scroll_enabled)
   IPC_STRUCT_TRAITS_MEMBER(show_paint_rects)
   IPC_STRUCT_TRAITS_MEMBER(render_vsync_enabled)
   IPC_STRUCT_TRAITS_MEMBER(asynchronous_spell_checking_enabled)
diff --git a/content/public/common/content_switches.cc b/content/public/common/content_switches.cc
index 6f1ca1c..0026aa8 100644
--- a/content/public/common/content_switches.cc
+++ b/content/public/common/content_switches.cc
@@ -552,6 +552,11 @@ const char kShowCompositedLayerTree[]       = "show-composited-layer-tree";
 // Draws a FPS indicator
 const char kShowFPSCounter[]                = "show-fps-counter";
 
+// Enables accelerated compositing for overflow scroll. Promotes eligible
+// overflow:scroll elements to layers to enable accelerated scrolling for them.
+const char kEnableAcceleratedCompositingForOverflowScroll[] =
+    "enable-accelerated-compositing-for-overflow-scroll";
+
 // Visibly render a border around paint rects in the web page to help debug
 // and study painting behavior.
 const char kShowPaintRects[]                = "show-paint-rects";
diff --git a/content/public/common/content_switches.h b/content/public/common/content_switches.h
index 4c25780..cdeff20 100644
--- a/content/public/common/content_switches.h
+++ b/content/public/common/content_switches.h
@@ -174,6 +174,7 @@ CONTENT_EXPORT extern const char kServiceProcess[];
 extern const char kShowCompositedLayerBorders[];
 extern const char kShowCompositedLayerTree[];
 extern const char kShowFPSCounter[];
+extern const char kEnableAcceleratedCompositingForOverflowScroll[];
 extern const char kShowPaintRects[];
 CONTENT_EXPORT extern const char kSimulateTouchScreenWithMouse[];
 CONTENT_EXPORT extern const char kSingleProcess[];
diff --git a/webkit/glue/webpreferences.cc b/webkit/glue/webpreferences.cc
index 3e16063..ea9992e 100644
--- a/webkit/glue/webpreferences.cc
+++ b/webkit/glue/webpreferences.cc
@@ -78,6 +78,7 @@ WebPreferences::WebPreferences()
       show_composited_layer_borders(false),
       show_composited_layer_tree(false),
       show_fps_counter(false),
+      accelerated_compositing_for_overflow_scroll_enabled(false),
       show_paint_rects(false),
       render_vsync_enabled(true),
       asynchronous_spell_checking_enabled(true),
@@ -309,6 +310,10 @@ void WebPreferences::Apply(WebView* web_view) const {
   // Display an FPS indicator if requested on the command line.
   settings->setShowFPSCounter(show_fps_counter);
 
+  // Enables accelerated compositing for overflow scroll.
+  settings->setAcceleratedCompositingForOverflowScrollEnabled(
+      accelerated_compositing_for_overflow_scroll_enabled);
+
   // Display the current compositor tree as overlay if requested on
   // the command line
   settings->setShowPlatformLayerTree(show_composited_layer_tree);
diff --git a/webkit/glue/webpreferences.h b/webkit/glue/webpreferences.h
index c414a5e..0e387f5ea 100644
--- a/webkit/glue/webpreferences.h
+++ b/webkit/glue/webpreferences.h
@@ -95,6 +95,7 @@ struct WEBKIT_GLUE_EXPORT WebPreferences {
   bool show_composited_layer_borders;
   bool show_composited_layer_tree;
   bool show_fps_counter;
+  bool accelerated_compositing_for_overflow_scroll_enabled;
   bool show_paint_rects;
   bool render_vsync_enabled;
   bool asynchronous_spell_checking_enabled;