cc: Allow 'overflow: hidden' layers to be scrolled again.

cc/layers/layer_impl.cc

Index: cc/layers/layer_impl.cc
diff --git a/cc/layers/layer_impl.cc b/cc/layers/layer_impl.cc
index e46f4db9cdcf3f8c4f86b43ec82f22f1b3c946ab..f60ae8187fec42d5352a38599e14f4151d2cee57 100644
--- a/cc/layers/layer_impl.cc
+++ b/cc/layers/layer_impl.cc
@@ -358,16 +358,6 @@ void LayerImpl::SetSentScrollDelta(gfx::Vector2d sent_scroll_delta) {
 
 gfx::Vector2dF LayerImpl::ScrollBy(gfx::Vector2dF scroll) {
   DCHECK(scrollable());
-  gfx::Vector2dF scroll_hidden;
-  if (!user_scrollable_horizontal_) {
-    scroll_hidden.set_x(scroll.x());
-    scroll.set_x(0.f);
-  }
-  if (!user_scrollable_vertical_) {
-    scroll_hidden.set_y(scroll.y());
-    scroll.set_y(0.f);
-  }
-
   gfx::Vector2dF min_delta = -scroll_offset_;
   gfx::Vector2dF max_delta = max_scroll_offset_ - scroll_offset_;
   // Clamp new_delta so that position + delta stays within scroll bounds.
@@ -375,7 +365,7 @@ gfx::Vector2dF LayerImpl::ScrollBy(gfx::Vector2dF scroll) {
   new_delta.SetToMax(min_delta);
   new_delta.SetToMin(max_delta);
   gfx::Vector2dF unscrolled =
-      ScrollDelta() + scroll + scroll_hidden - new_delta;
+      ScrollDelta() + scroll - new_delta;
   SetScrollDelta(new_delta);
   return unscrolled;
 }
@@ -476,13 +466,6 @@ InputHandler::ScrollStatus LayerImpl::TryScroll(
     return InputHandler::ScrollIgnored;
   }
 
-  if (!user_scrollable_horizontal_ && !user_scrollable_vertical_) {
-    TRACE_EVENT0("cc",
-                 "LayerImpl::TryScroll: Ignored. User gesture is not allowed"
-                 " to scroll this layer.");
-    return InputHandler::ScrollIgnored;
-  }
-
   return InputHandler::ScrollStarted;
 }