cc: Do not allow gesture-scrolling 'overflow[-{x|y}]:hidden' layers.

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 d42ec311f966c4dcbd32cfc7f166dc3f64ef90f8..ad9a1caca8bfc06493151d490ba5d85695a7fff7 100644
--- a/cc/layers/layer_impl.cc
+++ b/cc/layers/layer_impl.cc
@@ -341,6 +341,10 @@ void LayerImpl::SetSentScrollDelta(gfx::Vector2d sent_scroll_delta) {
 
 gfx::Vector2dF LayerImpl::ScrollBy(gfx::Vector2dF scroll) {
   DCHECK(scrollable());
+  if (!horizontal_scrollbar_layer_)
+    scroll.set_x(0.f);

[danakj, 2013/10/21 15:14:42]

This would eat the whole scroll but not perform it, ie return unscrolled would
return 0 along this axis. Is that the intent here?

[sadrul, 2013/10/21 16:19:14]

That wasn't intentional. Fixed. Thanks!

+  if (!vertical_scrollbar_layer_)
+    scroll.set_y(0.f);
 
   gfx::Vector2dF min_delta = -scroll_offset_;
   gfx::Vector2dF max_delta = max_scroll_offset_ - scroll_offset_;
@@ -449,6 +453,9 @@ InputHandler::ScrollStatus LayerImpl::TryScroll(
     return InputHandler::ScrollIgnored;
   }
 
+  if (!horizontal_scrollbar_layer_ && !vertical_scrollbar_layer_)
+    return InputHandler::ScrollIgnored;
+
   return InputHandler::ScrollStarted;
 }