[Android] Disable fling cancel filtering in the GestureEventQueue

content/browser/renderer_host/input/gesture_event_queue.h

 // Copyright 2014 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_GESTURE_EVENT_QUEUE_H_
 #define CONTENT_BROWSER_RENDERER_HOST_INPUT_GESTURE_EVENT_QUEUE_H_
 
 #include <deque>
 
 #include "base/basictypes.h"
@@ skipping 55 matching lines @@
     // Controls touchpad-related tap suppression, disabled by default.
     TapSuppressionController::Config touchpad_tap_suppression_config;
 
     // Controls touchscreen-related tap suppression, disabled by default.
     TapSuppressionController::Config touchscreen_tap_suppression_config;
 
     // Determines whether non-scroll gesture events are "debounced" during an
     // active scroll sequence, suppressing brief scroll interruptions.
     // Zero by default (disabled).
     base::TimeDelta debounce_interval;
+
+    // Whether to filter unnecessary GestureFlingCancel events. Filtering should
+    // be disabled if there may be content-targetting fling curves about which
+    // the renderer is unaware (e.g., with Android WebView).
+    // True by default.
+    bool enable_fling_cancel_filtering;
   };
 
   // Both |client| and |touchpad_client| must outlive the GestureEventQueue.
   GestureEventQueue(GestureEventQueueClient* client,
                     TouchpadTapSuppressionControllerClient* touchpad_client,
                     const Config& config);
   ~GestureEventQueue();
 
   // Adds a gesture to the queue if it passes the relevant filters. If
   // there are no events currently queued, the event will be forwarded
@@ skipping 66 matching lines @@
   void QueueScrollOrPinchAndForwardIfNecessary(
       const GestureEventWithLatencyInfo& gesture_event);
 
   // The number of sent events for which we're awaiting an ack.  These events
   // remain at the head of the queue until ack'ed.
   size_t EventsInFlightCount() const;
 
   // The receiver of all forwarded gesture events.
   GestureEventQueueClient* client_;
 
+  // Whether to filter unnecessary GestureFlingCancel events.
+  bool enable_fling_cancel_filtering_;
+
   // Whether there are any active flings in the renderer. As the fling
   // end notification is asynchronous, we use a count rather than a boolean
   // to avoid races in bookkeeping when starting a new fling.
   int active_fling_count_;
 
   // True if a GestureScrollUpdate sequence is in progress.
   bool scrolling_in_progress_;
 
   // True if two related gesture events were sent before without waiting
   // for an ACK, so the next gesture ACK should be ignored.
@@ skipping 30 matching lines @@
   // Time window in which to debounce scroll/fling ends. Note that an interval
   // of zero effectively disables debouncing.
   base::TimeDelta debounce_interval_;
 
   DISALLOW_COPY_AND_ASSIGN(GestureEventQueue);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_INPUT_GESTURE_EVENT_QUEUE_H_