Rename GestureEventQueue to TouchDispositionGestureFilter

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 <queue>
-
-#include "content/browser/renderer_host/input/gesture_event_packet.h"
-#include "content/common/content_export.h"
-#include "content/port/common/input_event_ack_state.h"
-#include "third_party/WebKit/public/web/WebInputEvent.h"
-
-namespace content {
-
-// Interface with which the |GestureEventQueue| forwards gestures for a given
-// touch event.
-class CONTENT_EXPORT GestureEventQueueClient {
- public:
-  virtual void ForwardGestureEvent(const blink::WebGestureEvent&) = 0;
-};
-
-// Handles dispatch of touch-derived gestures created by the platform.
-// Gestures are forwarded or dropped depending on the ack dispositions of the
-// generating touch sequence.
-class CONTENT_EXPORT GestureEventQueue {
- public:
-  explicit GestureEventQueue(GestureEventQueueClient* client);
-  ~GestureEventQueue();
-
-  // To be called upon receipt of gesture-related events.  In particular,
-  // |packet| contains [0, n] gestures that correspond to a given event.  That
-  // event may be a touch, or a touch timeout for certain stationary gestures.
-  // It is imperative that a single packet is received for *each* touch event,
-  // even those that did not produce a gesture.
-  void OnGestureEventPacket(const GestureEventPacket& packet);
-
-  // To be called upon receipt of *all* touch event acks.
-  void OnTouchEventAck(InputEventAckState ack_state);
-
- private:
-  // Utility class for tracking gesture events and dispositions for a single
-  // gesture sequence. A single sequence corresponds to all gestures created
-  // between the first finger down and the last finger up, including gestures
-  // generated by timeouts from a statinoary finger.
-  class GestureSequence {
-   public:
-    GestureSequence();
-    ~GestureSequence();
-
-    void Push(const GestureEventPacket& packet);
-    void Pop();
-    const GestureEventPacket& Front() const;
-    void UpdateState(InputEventAckState ack_state);
-    bool IsGesturePrevented() const;
-    bool IsEmpty() const;
-
-   private:
-    std::queue<GestureEventPacket> packets_;
-    enum GestureHandlingState {
-      PENDING,                 // The sequence has yet to receive an ack.
-      ALLOWED_UNTIL_PREVENTED, // Gestures in the sequence are allowed until
-                               // a source touch is preventDefault'ed.
-      ALWAYS_ALLOWED,          // All remaining sequence gestures are forwarded.
-      ALWAYS_PREVENTED         // All remaining sequence gestures are dropped.
-    };
-    GestureHandlingState state_;
-  };
-  void UpdateAndDispatchPackets(GestureSequence* sequence,
-                                InputEventAckState ack_result);
-  void SendPacket(const GestureEventPacket& packet);
-  void SendGesture(const blink::WebGestureEvent& gesture);
-  void CancelTapIfNecessary();
-  void CancelFlingIfNecessary();
-  GestureSequence& Head();
-  GestureSequence& Tail();
-
-  GestureEventQueueClient* client_;
-  std::queue<GestureSequence> sequences_;
-
-  // Bookkeeping for inserting synthetic Gesture{Tap,Fling}Cancel events
-  // when necessary, e.g., GestureTapCancel when scrolling begins, or
-  // GestureFlingCancel when a user taps following a GestureFlingStart.
-  bool needs_tap_ending_event_;
-  bool needs_fling_ending_event_;
-
-  DISALLOW_COPY_AND_ASSIGN(GestureEventQueue);
-};
-
-}  // namespace content
-
-#endif  // CONTENT_BROWSER_RENDERER_HOST_INPUT_GESTURE_EVENT_QUEUE_H_