Explicit interface for synchronous InputHandlerProxy input handling

content/renderer/gpu/input_handler_proxy.h

 // Copyright (c) 2013 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 CONTENT_RENDERER_GPU_INPUT_HANDLER_PROXY_H_
 #define CONTENT_RENDERER_GPU_INPUT_HANDLER_PROXY_H_
 
 #include "base/basictypes.h"
 #include "base/hash_tables.h"
 #include "base/memory/scoped_ptr.h"
 #include "cc/input/input_handler.h"
 #include "content/common/content_export.h"
+#include "content/port/common/input_event_ack_state.h"
 #include "third_party/WebKit/public/platform/WebGestureCurve.h"
 #include "third_party/WebKit/public/platform/WebGestureCurveTarget.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebActiveWheelFlingParameters.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebInputEvent.h"
 
 namespace content {
 
 class InputHandlerProxyClient;
 
 // This class is a proxy between the content input event filtering and the
 // compositor's input handling logic. InputHandlerProxy instances live entirely
 // on the compositor thread. Each InputHandler instance handles input events
 // intended for a specific WebWidget.
 class CONTENT_EXPORT InputHandlerProxy
     : public cc::InputHandlerClient,
       public NON_EXPORTED_BASE(WebKit::WebGestureCurveTarget) {
  public:
   explicit InputHandlerProxy(cc::InputHandler* input_handler);
   virtual ~InputHandlerProxy();
 
   void SetClient(InputHandlerProxyClient* client);
-  void HandleInputEvent(const WebKit::WebInputEvent& event);
+
+  enum EventDisposition {
+    EVENT_DISPOSITION_DID_HANDLE,

[jamesr, 2013/06/03 22:07:44]

nit: the whole "put the enum name in the enum values" thing is a holdover from
the WebKit API style. you don't need to do that here - so long as the enum
values don't collide they can be shorter. up to you

[jdduke (slow), 2013/06/03 22:31:03]

Oh heck yes.  I'll update.

+    EVENT_DISPOSITION_DID_NOT_HANDLE,
+    EVENT_DISPOSITION_DROP_EVENT
+  };
+  EventDisposition HandleInputEvent(const WebKit::WebInputEvent& event);
 
   // cc::InputHandlerClient implementation.
   virtual void WillShutdown() OVERRIDE;
   virtual void Animate(base::TimeTicks time) OVERRIDE;
   virtual void MainThreadHasStoppedFlinging() OVERRIDE;
   virtual void DidOverscroll(gfx::Vector2dF accumulated_overscroll,
                              gfx::Vector2dF current_fling_velocity) OVERRIDE;
 
   // WebKit::WebGestureCurveTarget implementation.
   virtual void scrollBy(const WebKit::WebFloatSize& offset);
   virtual void notifyCurrentFlingVelocity(const WebKit::WebFloatSize& velocity);
 
   bool gesture_scroll_on_impl_thread_for_testing() const {
     return gesture_scroll_on_impl_thread_;
   }
 
  private:
-  enum EventDisposition {
-    DidHandle,
-    DidNotHandle,
-    DropEvent
-  };
   // This function processes the input event and determines the disposition, but
   // does not make any calls out to the InputHandlerProxyClient. Some input
   // types defer to helpers.
   EventDisposition HandleInputEventInternal(const WebKit::WebInputEvent& event);
 
   EventDisposition HandleGestureFling(const WebKit::WebGestureEvent& event);
 
   // Returns true if we scrolled by the increment.
   bool TouchpadFlingScroll(const WebKit::WebFloatSize& increment);
 
@@ skipping 18 matching lines @@
   // conservative in the sense that we might not be actually flinging when it is
   // true.
   bool fling_may_be_active_on_main_thread_;
 
   DISALLOW_COPY_AND_ASSIGN(InputHandlerProxy);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_GPU_INPUT_HANDLER_PROXY_H_