Implement pinch-zoom scaling for main-frame scrollbars and pinch-zoom overlay scrollbars.

webkit/compositor_bindings/web_scrollbar_layer_impl.cc

Index: webkit/compositor_bindings/web_scrollbar_layer_impl.cc
diff --git a/webkit/compositor_bindings/web_scrollbar_layer_impl.cc b/webkit/compositor_bindings/web_scrollbar_layer_impl.cc
index 75cc3a7279ae70b00bc2de907475f9430554e3f2..b435cc52eda57b47dc0dba53389ef3b41479860a 100644
--- a/webkit/compositor_bindings/web_scrollbar_layer_impl.cc
+++ b/webkit/compositor_bindings/web_scrollbar_layer_impl.cc
@@ -39,6 +39,14 @@ void WebScrollbarLayerImpl::setScrollLayer(WebLayer* layer)
     static_cast<ScrollbarLayer*>(m_layer->layer())->setScrollLayerId(id);
 }
 
+void WebScrollbarLayerImpl::setDefaultGeometry(WebScrollbarThemeGeometry* geometry)
+{
+    ScrollbarLayer::setDefaultGeometry(geometry);
+}
 
+void WebScrollbarLayerImpl::setDefaultUsesOverlayScrollbars(bool usesOverlayScrollbars)
+{
+    ScrollbarLayer::setDefaultUsesOverlayScrollbars(usesOverlayScrollbars);
+}
 
 } // namespace WebKit