Remove the touch ack timeout handler out of the legacy touch event queue.

content/browser/renderer_host/input/touch_timeout_handler.h

+// Copyright 2017 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_TIMEOUT_HANDLER_H_
+#define CONTENT_BROWSER_RENDERER_HOST_INPUT_TOUCH_TIMEOUT_HANDLER_H_
+
+#include <stddef.h>
+#include <stdint.h>
+
+#include "base/macros.h"
+#include "base/time/time.h"
+#include "content/browser/renderer_host/event_with_latency_info.h"
+#include "content/browser/renderer_host/input/timeout_monitor.h"
+#include "content/common/input/input_event_ack_state.h"
+
+namespace content {
+
+class TouchEventQueue;
+
+class TouchTimeoutHandler {
+ public:
+  TouchTimeoutHandler(TouchEventQueue* touch_queue,
+                      base::TimeDelta desktop_timeout_delay,
+                      base::TimeDelta mobile_timeout_delay);
+
+  ~TouchTimeoutHandler();
+
+  void StartIfNecessary(const TouchEventWithLatencyInfo& event);
+  bool ConfirmTouchEvent(uint32_t unique_touch_event_id,
+                         InputEventAckState ack_result);
+  bool FilterEvent(const blink::WebTouchEvent& event);
+  void SetEnabled(bool enabled);
+  void SetUseMobileTimeout(bool use_mobile_timeout);
+  bool IsTimeoutTimerRunning() const { return timeout_monitor_.IsRunning(); }
+  bool IsEnabled() const { return enabled_ && !GetTimeoutDelay().is_zero(); }
+
+ private:
+  enum PendingAckState {
+    PENDING_ACK_NONE,
+    PENDING_ACK_ORIGINAL_EVENT,
+    PENDING_ACK_CANCEL_EVENT,
+  };
+
+  void OnTimeOut();
+  // Skip a cancel event if the timed-out event had no consumer and was the
+  // initial event in the gesture.
+  bool AckedTimeoutEventRequiresCancel(InputEventAckState ack_result) const;
+  void SetPendingAckState(PendingAckState new_pending_ack_state);
+  void LogSequenceStartForUMA();
+  void LogSequenceEndForUMAIfNecessary(bool timed_out);
+  base::TimeDelta GetTimeoutDelay() const;
+  bool HasTimeoutEvent() const;
+
+  TouchEventQueue* touch_queue_;
+
+  // How long to wait on a touch ack before cancelling the touch sequence.
+  const base::TimeDelta desktop_timeout_delay_;
+  const base::TimeDelta mobile_timeout_delay_;
+  bool use_mobile_timeout_;
+
+  // The touch event source for which we expect the next ack.
+  PendingAckState pending_ack_state_;
+
+  // The event for which the ack timeout is triggered.
+  TouchEventWithLatencyInfo timeout_event_;
+
+  // Provides timeout-based callback behavior.
+  TimeoutMonitor timeout_monitor_;
+
+  bool enabled_;
+  bool enabled_for_current_sequence_;
+
+  // Bookkeeping to classify and log whether a touch sequence times out.
+  bool sequence_awaiting_uma_update_;
+  bool sequence_using_mobile_timeout_;
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_RENDERER_HOST_INPUT_TOUCH_TIMEOUT_HANDLER_H_