Some touch-event forwarding optimization.

content/browser/renderer_host/render_widget_host.h

 // Copyright (c) 2012 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_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_H_
 #define CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_H_
 #pragma once
 
 #include <deque>
 #include <string>
@@ skipping 381 matching lines @@
   }
   bool ignore_input_events() const {
     return ignore_input_events_;
   }
 
   // Activate deferred plugin handles.
   void ActivateDeferredPluginHandles();
 
   const gfx::Point& last_scroll_offset() const { return last_scroll_offset_; }
 
+  bool has_touch_handler() const { return has_touch_handler_; }
+
   // Notification that the user has made some kind of input that could
   // perform an action. See OnUserGesture for more details.
   void StartUserGesture();
 
   // Stops loading the page.
   void Stop();
 
   // Set the RenderView background.
   void SetBackground(const SkBitmap& background);
 
@@ skipping 161 matching lines @@
   void OnMsgRequestMove(const gfx::Rect& pos);
   void OnMsgSetTooltipText(const string16& tooltip_text,
                            WebKit::WebTextDirection text_direction_hint);
   void OnMsgPaintAtSizeAck(int tag, const gfx::Size& size);
   void OnMsgUpdateRect(const ViewHostMsg_UpdateRect_Params& params);
   void OnMsgUpdateIsDelayed();
   void OnMsgInputEventAck(WebKit::WebInputEvent::Type event_type,
                           bool processed);
   virtual void OnMsgFocus();
   virtual void OnMsgBlur();
+  void OnMsgDidChangeNumTouchEvents(int count);
 
   void OnMsgSetCursor(const WebCursor& cursor);
   void OnMsgTextInputStateChanged(ui::TextInputType type,
                                   bool can_compose_inline);
   void OnMsgImeCompositionRangeChanged(const ui::Range& range);
   void OnMsgImeCancelComposition();
 
   void OnMsgDidActivateAcceleratedCompositing(bool activated);
 
   void OnMsgLockMouse();
@@ skipping 209 matching lines @@
   // changed.
   bool suppress_next_char_events_;
 
   std::vector<gfx::PluginWindowHandle> deferred_plugin_handles_;
 
   // The last scroll offset of the render widget.
   gfx::Point last_scroll_offset_;
 
   bool pending_mouse_lock_request_;
 
+  // Keeps track of whether the webpage has any touch event handler. If it does,
+  // then touch events are sent to the renderer. Otherwise, the touch events are
+  // not sent to the renderer.
+  bool has_touch_handler_;
+
   base::WeakPtrFactory<RenderWidgetHost> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderWidgetHost);
 };
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_H_