[Android] Always insert a TouchCancel if window or tab focus is lost

ui/events/gesture_detection/gesture_provider.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 UI_EVENTS_GESTURE_DETECTION_GESTURE_PROVIDER_H_
 #define UI_EVENTS_GESTURE_DETECTION_GESTURE_PROVIDER_H_
 
 #include "base/basictypes.h"
 #include "base/memory/scoped_ptr.h"
 #include "ui/events/gesture_detection/gesture_detection_export.h"
@@ skipping 30 matching lines @@
   // Handle the incoming MotionEvent, returning false if the event could not
   // be handled.
   bool OnTouchEvent(const MotionEvent& event);
 
   // Resets all gesture detectors; called on DidStartLoading().
   void ResetGestureDetectors();
 
   // Cancel the current touch event sequence by sending ACTION_CANCEL, and
   // ignore all the subsequent events until the next ACTION_DOWN.
   // One example usecase is to stop processing the touch events when showing
-  // a context popup menu.
-  void CancelActiveTouchSequence();
+  // a context popup menu. Returns true if there was an active touch sequence at
+  // the time of cancellation.
+  bool CancelActiveTouchSequence();
 
   // Update whether multi-touch gestures are supported.
   void SetMultiTouchSupportEnabled(bool enabled);
 
   // Update whether double-tap gestures are supported. This allows
   // double-tap gesture suppression independent of whether or not the page's
   // viewport and scale would normally prevent double-tap.
   // Note: This should not be called while a double-tap gesture is in progress.
   void SetDoubleTapSupportForPlatformEnabled(bool enabled);
 
   // Update whether double-tap gesture detection should be suppressed due to
   // the viewport or scale of the current page. Suppressing double-tap gesture
   // detection allows for rapid and responsive single-tap gestures.
   void SetDoubleTapSupportForPageEnabled(bool enabled);
 
   // Whether a scroll gesture is in-progress.
   bool IsScrollInProgress() const;
 
   // Whether a pinch gesture is in-progress (i.e. a pinch update has been
   // forwarded and detection is still active).
   bool IsPinchInProgress() const;
 
   // Whether a double tap-gesture is in-progress.
   bool IsDoubleTapInProgress() const;
 
   // Whether the tap gesture delay is explicitly disabled (independent of
   // whether double-tap is supported), see |Config.disable_click_delay|.
   bool IsClickDelayDisabled() const;
 
+  // May be NULL if there is no currently active touch sequence.
+  const ui::MotionEvent* current_down_event() const {
+    return current_down_event_.get();
+  }
+
  private:
   void InitGestureDetectors(const Config& config);
 
   bool CanHandle(const MotionEvent& event) const;
 
   void Fling(base::TimeTicks time,
              float x,
              float y,
              float velocity_x,
              float velocity_y);
@@ skipping 31 matching lines @@
 
   // Keeps track of the current GESTURE_LONG_PRESS event. If a context menu is
   // opened after a GESTURE_LONG_PRESS, this is used to insert a
   // GESTURE_TAP_CANCEL for removing any ::active styling.
   base::TimeTicks current_longpress_time_;
 };
 
 }  //  namespace ui
 
 #endif  // UI_EVENTS_GESTURE_DETECTION_GESTURE_PROVIDER_H_