Add POINTER_WHEEL_CHANGED event to mojo.

ui/events/event.cc

 // Copyright (c) 2012 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 "ui/events/event.h"
 
 #include <utility>
 
 #include "base/memory/ptr_util.h"
 
@@ skipping 480 matching lines @@
 
     case ET_POINTER_EXITED:
       SetType(ET_MOUSE_EXITED);
       break;
 
     case ET_POINTER_UP:
       SetType(ET_MOUSE_RELEASED);
       break;
 
     case ET_POINTER_WHEEL_CHANGED:
       SetType(ET_MOUSEWHEEL);

[sadrul, 2016/09/01 05:38:54]

Can you change this to a NOTREACHED()?

[riajiang, 2016/09/01 15:29:21]

As discussed, changing it to not set type here. Also changing some DCHECKs.

       break;
 
     case ET_POINTER_CAPTURE_CHANGED:
       SetType(ET_MOUSE_CAPTURE_CHANGED);
       break;
 
     default:
       NOTREACHED();
   }
 }
@@ skipping 143 matching lines @@
       offset_(GetMouseWheelOffset(native_event)) {
 }
 
 MouseWheelEvent::MouseWheelEvent(const ScrollEvent& scroll_event)
     : MouseEvent(scroll_event),
       offset_(gfx::ToRoundedInt(scroll_event.x_offset()),
               gfx::ToRoundedInt(scroll_event.y_offset())) {
   SetType(ET_MOUSEWHEEL);
 }
 
+MouseWheelEvent::MouseWheelEvent(const PointerEvent& pointer_event)
+    : MouseEvent(pointer_event),
+      offset_(pointer_event.pointer_details().offset.x(),
+              pointer_event.pointer_details().offset.y()) {
+  DCHECK(type() == ET_MOUSEWHEEL);
+}
+
 MouseWheelEvent::MouseWheelEvent(const MouseEvent& mouse_event,
                                  int x_offset,
                                  int y_offset)
     : MouseEvent(mouse_event), offset_(x_offset, y_offset) {
   DCHECK(type() == ET_MOUSEWHEEL);
 }
 
 MouseWheelEvent::MouseWheelEvent(const MouseWheelEvent& mouse_wheel_event)
     : MouseEvent(mouse_wheel_event),
       offset_(mouse_wheel_event.offset()) {
@@ skipping 631 matching lines @@
                    gfx::PointF(x, y),
                    time_stamp,
                    flags | EF_FROM_TOUCH),
       details_(details),
       unique_touch_event_id_(unique_touch_event_id) {}
 
 GestureEvent::~GestureEvent() {
 }
 
 }  // namespace ui