Set the unique_event_id when converting from TouchEvent to WebTouchEvent

ui/events/blink/blink_event_util.cc

 // 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.
 
 // MSVC++ requires this to be set before any other includes to get M_PI.
 #define _USE_MATH_DEFINES
 
 #include "ui/events/blink/blink_event_util.h"
 
 #include <cmath>
@@ skipping 124 matching lines @@
                 "inconsistent maximum number of active touch points");
 
   blink::WebTouchEvent result;
 
   result.type = ToWebInputEventType(event.GetAction());
   result.cancelable = (result.type != WebInputEvent::TouchCancel);
   result.timeStampSeconds =
       (event.GetEventTime() - base::TimeTicks()).InSecondsF(),
   result.causesScrollingIfUncanceled = may_cause_scrolling;
   result.modifiers = EventFlagsToWebEventModifiers(event.GetFlags());
+  DCHECK_NE(event.GetUniqueEventId(), 0U);
+  result.uniqueTouchEventId = event.GetUniqueEventId();
   result.touchesLength =
       std::min(static_cast<unsigned>(event.GetPointerCount()),
                static_cast<unsigned>(WebTouchEvent::touchesLengthCap));
   DCHECK_GT(result.touchesLength, 0U);
 
   for (size_t i = 0; i < result.touchesLength; ++i)
     result.touches[i] = CreateWebTouchPoint(event, i);
 
   return result;
 }
@@ skipping 139 matching lines @@
 }
 
 WebGestureEvent CreateWebGestureEventFromGestureEventData(
     const GestureEventData& data) {
   return CreateWebGestureEvent(data.details, data.time - base::TimeTicks(),
                                gfx::PointF(data.x, data.y),
                                gfx::PointF(data.raw_x, data.raw_y), data.flags);
 }
 
 }  // namespace ui