Suppress touchscreen tap immediately after a GestureFlingCancel

content/browser/renderer_host/touchscreen_tap_suppression_controller.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_BROWSER_RENDERER_HOST_TOUCHSCREEN_TAP_SUPPRESSION_CONTROLLER_H_

[rjkroege, 2013/02/05 16:00:07]

there is a lot of code here in-common with touchpad_tap_suppression. I think it
would be a good idea to factor out this duplication yes?

+#define CONTENT_BROWSER_RENDERER_HOST_TOUCHSCREEN_TAP_SUPPRESSION_CONTROLLER_H_
+
+#include "base/time.h"
+#include "base/timer.h"
+#include "third_party/WebKit/Source/WebKit/chromium/public/WebInputEvent.h"
+
+namespace content {
+
+class GestureEventFilter;
+class MockRenderWidgetHost;
+class RenderWidgetHostImpl;
+
+// Controls the suppression of touchscreen taps (rapid gesture tapdown/tap
+// sequences) immediately following the dispatch of a GestureFlingCancel event.
+// Only tapdown/tap's of sufficient speed and within a specified time window
+// after a GestureFlingCancel are suppressed.
+class TouchscreenTapSuppressionController {
+ public:
+  explicit TouchscreenTapSuppressionController(RenderWidgetHostImpl* rwhv,
+                                               GestureEventFilter* gef);
+  ~TouchscreenTapSuppressionController();
+
+  // Called on the dispatch of a GestureFlingCancel event.
+  void GestureFlingCancel(double cancel_time);
+
+  // Called on an ack of GestureFlingCancel event. |processed| is true when
+  // the GestureFlingCancel actually stopped a fling and therefore should
+  // suppress the forwarding of the following tap.
+  void GestureFlingCancelAck(bool processed);
+
+  // Called on a gesture tapdown. Returns true if the hosting RWHV should not
+  // continue with handling the gesture tapdown event at this time.
+  bool ShouldDeferGestureTapDown(const WebKit::WebGestureEvent& event);
+
+  // Called on the arrival of a gesture tap event. Returns true if the hosting
+  // RWHV should suppress the remaining gesture tap handling at this time.
+  bool ShouldSuppressGestureTap();
+
+  // Called on the arrival of a gesture tapcancel event. Returns true if the
+  // hosting RWHV should suppress the remaining gesture tapcancel handling at
+  // this time.
+  bool ShouldSuppressGestureTapCancel();
+
+ private:
+  friend class MockRenderWidgetHost;
+
+   enum State {
+     NOTHING,
+     GFC_IN_PROGRESS,
+     GTD_STASHED,
+     LAST_CANCEL_STOPPED_FLING,
+  };
+
+  // Invoked once the maximum time deemed a tap from a gesture tapdown event
+  // has expired. If the gesture tap has not yet arrived, indicates that the
+  // gesture tapdown/tap pair do not form a tap.
+  void GestureTapDownTimerExpired();
+
+  RenderWidgetHostImpl* render_widget_host_;
+  GestureEventFilter* gesture_event_filter_;
+
+  base::OneShotTimer<TouchscreenTapSuppressionController> tap_down_timer_;
+  WebKit::WebGestureEvent stashed_tap_down_;
+  State state_;
+
+  // TODO(rjkroege): During debugging, the event times did not prove reliable.

[rjkroege, 2013/02/05 16:00:07]

You're adding this code. You get to take the TODO over. :-)

[mohsen, 2013/02/06 16:13:06]

Yep, Sorry :-) Done.

+  // Replace the use of base::TimeTicks with an accurate event time when they
+  // become available post http://crbug.com/119556.
+  base::TimeTicks fling_cancel_time_;
+
+  DISALLOW_COPY_AND_ASSIGN(TouchscreenTapSuppressionController);
+};
+
+} // namespace content
+
+#endif  // CONTENT_BROWSER_RENDERER_HOST_TOUCHSCREEN_TAP_SUPPRESSION_CONTROLLER_H_