cc: Damage layer on delegated scroll

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 6dfec0e7d71c2069e3666f34d1371dbd275128fc..ee3742f2c2faf9e1f8c8981bf6f7ed65f8e5e018 100644
--- a/cc/layers/layer_impl.cc
+++ b/cc/layers/layer_impl.cc
@@ -1079,6 +1079,11 @@ bool LayerImpl::IsExternalFlingActive() const {
          scroll_offset_delegate_->IsExternalFlingActive();
 }
 
+void LayerImpl::OnDelegatedScrollOffsetChanged() {
+  NoteLayerPropertyChangedForSubtree();
+  ScrollbarParametersDidChange(false);
+}
+
 void LayerImpl::SetScrollOffset(const gfx::ScrollOffset& scroll_offset) {
   SetScrollOffsetAndDelta(scroll_offset, ScrollDelta());
 }
@@ -1122,8 +1127,7 @@ void LayerImpl::SetScrollOffsetAndDelta(const gfx::ScrollOffset& scroll_offset,
   }
 
   if (changed) {
-    NoteLayerPropertyChangedForSubtree();
-    ScrollbarParametersDidChange(false);
+    OnDelegatedScrollOffsetChanged();

[enne (OOO), 2014/10/10 18:10:17]

bikeshed: This isn't really just for "delegated" if you call it here.  Also, it
gets called when either delta or offset changes, so it's not just "Offset"
either.  What about DidScroll?

[boliu, 2014/10/10 18:23:11]

Sounds good. Done.

   }
 }