Hook ScrollElasticityController to InputHandlerProxy

cc/input/input_handler.h

Index: cc/input/input_handler.h
diff --git a/cc/input/input_handler.h b/cc/input/input_handler.h
index 7a9c991968753055c10eb580956f7173eabdbd04..fbe852300aed72055248634f69f4556ada6ad777 100644
--- a/cc/input/input_handler.h
+++ b/cc/input/input_handler.h
@@ -24,6 +24,7 @@ namespace ui { struct LatencyInfo; }
 namespace cc {
 
 class LayerScrollOffsetDelegate;
+class ScrollElasticityHelper;
 
 struct CC_EXPORT InputHandlerScrollResult {
   InputHandlerScrollResult();
@@ -150,6 +151,8 @@ class CC_EXPORT InputHandler {
   virtual scoped_ptr<SwapPromiseMonitor> CreateLatencyInfoSwapPromiseMonitor(
       ui::LatencyInfo* latency) = 0;
 
+  virtual ScrollElasticityHelper* GetScrollElasticityHelper() = 0;
+
  protected:
   InputHandler() {}
   virtual ~InputHandler() {}