Prevent partial touch sequences from reaching the renderer

content/browser/renderer_host/input/touch_event_queue.h

 // Copyright 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_BROWSER_RENDERER_HOST_INPUT_TOUCH_EVENT_QUEUE_H_
 #define CONTENT_BROWSER_RENDERER_HOST_INPUT_TOUCH_EVENT_QUEUE_H_
 
 #include <deque>
 #include <map>
 
@@ skipping 64 matching lines @@
 
   size_t size() const {
     return touch_queue_.size();
   }
 
   bool ack_timeout_enabled() const {
     return ack_timeout_enabled_;
   }
 
   bool has_handlers() const {
-    return has_handlers_;
+    return touch_filtering_state_ != DROP_ALL_TOUCHES;
   }
 
  private:
   class TouchTimeoutHandler;
   friend class TouchTimeoutHandler;
   friend class TouchEventQueueTest;
 
   bool HasTimeoutEvent() const;
   bool IsTimeoutRunningForTesting() const;
   const TouchEventWithLatencyInfo& GetLatestEventForTesting() const;
@@ skipping 30 matching lines @@
 
   // Used to defer touch forwarding when ack dispatch triggers |QueueEvent()|.
   // If not NULL, |dispatching_touch_ack_| is the touch event of which the ack
   // is being dispatched.
   CoalescedWebTouchEvent* dispatching_touch_ack_;
 
   // Used to prevent touch timeout scheduling if we receive a synchronous
   // ack after forwarding a touch event to the client.
   bool dispatching_touch_;
 
-  // Whether there are any registered touch handlers. Defaults to false.
-  bool has_handlers_;
-
-  // Don't send touch events to the renderer while scrolling.
-  bool scroll_in_progress_;
-
-  // Whether an event in the current (multi)touch sequence was consumed by the
-  // renderer.  The touch timeout will never be activated when this is true.
-  bool renderer_is_consuming_touch_gesture_;
+  enum TouchFilteringState {
+    FORWARD_ALL_TOUCHES,           // Don't filter at all - the default.
+    FORWARD_TOUCHES_UNTIL_TIMEOUT, // Don't filter unless we get an ACK timeout.
+    DROP_TOUCHES_IN_SEQUENCE,      // Filter all events until a new touch
+                                   // sequence is received.
+    DROP_ALL_TOUCHES,              // Filter all events, e.g., no touch handler.
+    TOUCH_FILTERING_STATE_DEFAULT = FORWARD_ALL_TOUCHES,
+  };
+  TouchFilteringState touch_filtering_state_;
 
   // Optional handler for timed-out touch event acks, disabled by default.
   bool ack_timeout_enabled_;
   scoped_ptr<TouchTimeoutHandler> timeout_handler_;
 
   DISALLOW_COPY_AND_ASSIGN(TouchEventQueue);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_INPUT_TOUCH_EVENT_QUEUE_H_