Enable pinch-zoom telemetry on Mac

content/browser/renderer_host/input/synthetic_touchpad_pinch_gesture.h

+// Copyright 2015 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_SYNTHETIC_TOUCHPAD_PINCH_GESTURE_H_
+#define CONTENT_BROWSER_RENDERER_HOST_INPUT_SYNTHETIC_TOUCHPAD_PINCH_GESTURE_H_
+
+#include "base/time/time.h"
+#include "content/browser/renderer_host/input/synthetic_gesture.h"
+#include "content/browser/renderer_host/input/synthetic_gesture_target.h"
+#include "content/common/content_export.h"
+#include "content/common/input/synthetic_pinch_gesture_params.h"
+#include "content/common/input/synthetic_web_input_event_builders.h"
+#include "third_party/WebKit/public/web/WebInputEvent.h"
+
+namespace content {
+
+class CONTENT_EXPORT SyntheticTouchpadPinchGesture : public SyntheticGesture {
+ public:
+  explicit SyntheticTouchpadPinchGesture(
+      const SyntheticPinchGestureParams& params);
+  ~SyntheticTouchpadPinchGesture() override;
+
+  SyntheticGesture::Result ForwardInputEvents(
+      const base::TimeTicks& timestamp,
+      SyntheticGestureTarget* target) override;
+
+ private:
+  enum GestureState { SETUP, STARTED, IN_PROGRESS, DONE };
+
+  void ForwardGestureEvents(const base::TimeTicks& timestamp,
+                            SyntheticGestureTarget* target);
+
+  void UpdateTouchPoints(const base::TimeTicks& timestamp);
+
+  void CalculateEndTime(SyntheticGestureTarget* target);
+  float CalculateTargetScale(const base::TimeTicks& timestamp) const;
+  base::TimeTicks ClampTimestamp(const base::TimeTicks& timestamp) const;
+  bool HasReachedTarget(const base::TimeTicks& timestamp) const;
+
+  SyntheticPinchGestureParams params_;
+  SyntheticGestureParams::GestureSourceType gesture_source_type_;
+  GestureState state_;
+  base::TimeTicks start_time_;
+  base::TimeTicks stop_time_;
+  float current_scale_;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(SyntheticTouchpadPinchGesture);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_RENDERER_HOST_INPUT_SYNTHETIC_TOUCHPAD_PINCH_GESTURE_H_