Implement windows mousewheel scroll by page functionality

webkit/compositor_bindings/web_to_ccinput_handler_adapter.cc

Index: webkit/compositor_bindings/web_to_ccinput_handler_adapter.cc
diff --git a/webkit/compositor_bindings/web_to_ccinput_handler_adapter.cc b/webkit/compositor_bindings/web_to_ccinput_handler_adapter.cc
index d079a0b57e3b0dccb9d5084b243dd9725c229459..dafde3c85dec289a9a31589c7fe2b2cb7870da64 100644
--- a/webkit/compositor_bindings/web_to_ccinput_handler_adapter.cc
+++ b/webkit/compositor_bindings/web_to_ccinput_handler_adapter.cc
@@ -52,6 +52,11 @@ class WebToCCInputHandlerAdapter::ClientAdapter : public WebInputHandlerClient {
     return client_->ScrollBy(point, delta);
   }
 
+  virtual bool scrollVerticallyByPageIfPossible(
+      WebPoint point, WebScrollbar::ScrollDirection direction) {
+    return client_->ScrollVerticallyByPage(point, direction);
+  }
+
   virtual void scrollEnd() { client_->ScrollEnd(); }
 
   virtual void pinchGestureBegin() { client_->PinchGestureBegin(); }