Communicate whether passive event listeners exist to cc.

cc/input/input_handler.h

 // Copyright 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CC_INPUT_INPUT_HANDLER_H_
 #define CC_INPUT_INPUT_HANDLER_H_
 
 #include "base/macros.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/time/time.h"
 #include "cc/base/cc_export.h"
+#include "cc/input/event_listener_properties.h"
 #include "cc/input/main_thread_scrolling_reason.h"
 #include "cc/input/scroll_state.h"
 #include "cc/input/scrollbar.h"
 #include "cc/trees/swap_promise_monitor.h"
 
 namespace gfx {
 class Point;
 class PointF;
 class ScrollOffset;
 class SizeF;
@@ skipping 141 matching lines @@
   // Request another callback to InputHandlerClient::Animate().
   virtual void SetNeedsAnimateInput() = 0;
 
   // Returns true if there is an active scroll on the inner viewport layer.
   virtual bool IsCurrentlyScrollingInnerViewport() const = 0;
 
   // Whether the layer under |viewport_point| is the currently scrolling layer.
   virtual bool IsCurrentlyScrollingLayerAt(const gfx::Point& viewport_point,
                                            ScrollInputType type) const = 0;
 
-  virtual bool HaveWheelEventHandlers() const = 0;
+  virtual EventListenerProperties GetEventListenerProperties(
+      EventListenerClass event_class) const = 0;
 
   // Whether the page should be given the opportunity to suppress scrolling by
   // consuming touch events that started at |viewport_point|.
   virtual bool DoTouchEventsBlockScrollAt(const gfx::Point& viewport_point) = 0;
 
   // Calling CreateLatencyInfoSwapPromiseMonitor() to get a scoped
   // LatencyInfoSwapPromiseMonitor. During the life time of the
   // LatencyInfoSwapPromiseMonitor, if SetNeedsRedraw() or SetNeedsRedrawRect()
   // is called on LayerTreeHostImpl, the original latency info will be turned
   // into a LatencyInfoSwapPromise.
   virtual scoped_ptr<SwapPromiseMonitor> CreateLatencyInfoSwapPromiseMonitor(
       ui::LatencyInfo* latency) = 0;
 
   virtual ScrollElasticityHelper* CreateScrollElasticityHelper() = 0;
 
  protected:
   InputHandler() {}
   virtual ~InputHandler() {}
 
  private:
   DISALLOW_COPY_AND_ASSIGN(InputHandler);
 };
 
 }  // namespace cc
 
 #endif  // CC_INPUT_INPUT_HANDLER_H_