Use WTF::TimeTicks to represent timestamp in Platform/Core event types

third_party/WebKit/Source/core/input/MouseEventManager.h

 // Copyright 2016 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 MouseEventManager_h
 #define MouseEventManager_h
 
 #include "core/CoreExport.h"
 #include "core/dom/SynchronousMutationObserver.h"
 #include "core/input/BoundaryEventDispatcher.h"
 #include "core/page/DragActions.h"
 #include "core/page/EventWithHitTestResults.h"
 #include "platform/PlatformMouseEvent.h"
 #include "platform/Timer.h"
 #include "public/platform/WebInputEventResult.h"
 #include "wtf/Allocator.h"
+#include "wtf/Time.h"
 
 namespace blink {
 
 class ContainerNode;
 class DragState;
 class DataTransfer;
 class Element;
 class FloatQuad;
 class HitTestResult;
 class InputDeviceCapabilities;
@@ skipping 182 matching lines @@
   unsigned m_svgPan : 1;
   unsigned m_capturesDragging : 1;
   unsigned m_mouseDownMayStartDrag : 1;
 
   Member<Node> m_mousePressNode;
 
   int m_clickCount;
   Member<Node> m_clickNode;
 
   IntPoint m_mouseDownPos;  // In our view's coords.
-  double m_mouseDownTimestamp;
+  TimeTicks m_mouseDownTimestamp;
   PlatformMouseEvent m_mouseDown;
 
   LayoutPoint m_dragStartPos;
 
   Timer<MouseEventManager> m_fakeMouseMoveEventTimer;
 };
 
 }  // namespace blink
 
 #endif  // MouseEventManager_h