Set the unique_event_id when converting from TouchEvent to WebTouchEvent

content/common/input/synthetic_web_input_event_builders.cc

 // Copyright 2013 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.
 
 #include "content/common/input/synthetic_web_input_event_builders.h"
 
 #include "base/logging.h"
 #include "content/common/input/web_touch_event_traits.h"
+#include "ui/events/base_event_utils.h"
 #include "ui/events/keycodes/keyboard_codes.h"
 
 namespace content {
 
 using blink::WebInputEvent;
 using blink::WebKeyboardEvent;
 using blink::WebGestureEvent;
 using blink::WebMouseEvent;
 using blink::WebMouseWheelEvent;
 using blink::WebTouchEvent;
@@ skipping 124 matching lines @@
     float velocity_y,
     blink::WebGestureDevice source_device) {
   WebGestureEvent result = Build(WebInputEvent::GestureFlingStart,
                                  source_device);
   result.data.flingStart.velocityX = velocity_x;
   result.data.flingStart.velocityY = velocity_y;
   return result;
 }
 
 SyntheticWebTouchEvent::SyntheticWebTouchEvent() : WebTouchEvent() {
+  uniqueTouchEventId = ui::GetNextTouchEventId();
   SetTimestamp(base::TimeTicks::Now() - base::TimeTicks());
 }
 
 void SyntheticWebTouchEvent::ResetPoints() {
   int point = 0;
   for (unsigned int i = 0; i < touchesLength; ++i) {
     if (touches[i].state == WebTouchPoint::StateReleased)
       continue;
 
     touches[point] = touches[i];
     touches[point].state = WebTouchPoint::StateStationary;
     ++point;
   }
   touchesLength = point;
   type = WebInputEvent::Undefined;
   causesScrollingIfUncanceled = false;
 }
 
 int SyntheticWebTouchEvent::PressPoint(float x, float y) {
   if (touchesLength == touchesLengthCap)
     return -1;
   WebTouchPoint& point = touches[touchesLength];

[jdduke (slow), 2015/04/28 16:26:58]

At some point, we'll probably need to assign a new ID each time a point is
manipulated (PressPoint/MovePoint/etc...). That doesn't necessarily need to
happen, but something to keep in mind when tests start relying on valid/unique
IDs.

   point.id = touchesLength;
   point.position.x = point.screenPosition.x = x;
   point.position.y = point.screenPosition.y = y;
   point.state = WebTouchPoint::StatePressed;
   point.radiusX = point.radiusY = 1.f;
   point.rotationAngle = 1.f;
   point.force = 1.f;
   ++touchesLength;
   WebTouchEventTraits::ResetType(
       WebInputEvent::TouchStart, timeStampSeconds, this);
@@ skipping 28 matching lines @@
   touches[index].state = WebTouchPoint::StateCancelled;
   WebTouchEventTraits::ResetType(
       WebInputEvent::TouchCancel, timeStampSeconds, this);
 }
 
 void SyntheticWebTouchEvent::SetTimestamp(base::TimeDelta timestamp) {
   timeStampSeconds = timestamp.InSecondsF();
 }
 
 }  // namespace content