Update ui::PointerEvent to support mouse wheel and capture change events.

ui/events/event.h

Index: ui/events/event.h
diff --git a/ui/events/event.h b/ui/events/event.h
index 850c290489025ee615ad13b23e086d402fcd0cea..50f4539355d8aa5eb1f388098d4b9da3ff2b3e2b 100644
--- a/ui/events/event.h
+++ b/ui/events/event.h
@@ -131,7 +131,9 @@ class EVENTS_EXPORT Event {
   bool IsPointerEvent() const {
     return type_ == ET_POINTER_DOWN || type_ == ET_POINTER_MOVED ||
            type_ == ET_POINTER_UP || type_ == ET_POINTER_CANCELLED ||
-           type_ == ET_POINTER_ENTERED || type_ == ET_POINTER_EXITED;
+           type_ == ET_POINTER_ENTERED || type_ == ET_POINTER_EXITED ||
+           type_ == ET_POINTER_WHEEL_CHANGED ||
+           type_ == ET_POINTER_CAPTURE_CHANGED;
   }
 
   // Convenience methods to check pointer type of |this|. Returns false if
@@ -412,15 +414,19 @@ struct EVENTS_EXPORT PointerDetails {
         force(force),
         tilt_x(tilt_x),
         tilt_y(tilt_y) {}
+  PointerDetails(EventPointerType pointer_type, int offset_x, int offset_y)
+      : pointer_type(pointer_type),
+        force(std::numeric_limits<float>::quiet_NaN()),
+        offset_x(offset_x),
+        offset_y(offset_y) {}
 
   bool operator==(const PointerDetails& other) const {
-    return pointer_type == other.pointer_type &&
-           radius_x == other.radius_x &&
+    return pointer_type == other.pointer_type && radius_x == other.radius_x &&
            radius_y == other.radius_y &&
            (force == other.force ||
             (std::isnan(force) && std::isnan(other.force))) &&
-           tilt_x == other.tilt_x &&
-           tilt_y == other.tilt_y;
+           tilt_x == other.tilt_x && tilt_y == other.tilt_y &&
+           offset_x == other.offset_x && offset_y == other.offset_y;
   }
 
   // The type of pointer device.
@@ -441,6 +447,12 @@ struct EVENTS_EXPORT PointerDetails {
   // is towards the user. 0.0 if unknown.
   float tilt_x = 0.0;
   float tilt_y = 0.0;
+
+  // Only used by mouse wheel events. The amount to scroll. This is in multiples
+  // of kWheelDelta.
+  // Note: x_offset() > 0/y_offset() > 0 means scroll left/up.
+  int offset_x = 0;
+  int offset_y = 0;

[sadrul, 2016/08/19 04:18:27]

Maybe use a gfx::Vector2dF instead?

[riajiang, 2016/08/19 16:19:39]

Done.

 };
 
 class EVENTS_EXPORT MouseEvent : public LocatedEvent {
@@ -713,9 +725,7 @@ class EVENTS_EXPORT PointerEvent : public LocatedEvent {
  public:
   static const int32_t kMousePointerId;
 
-  // Returns true if a PointerEvent can be constructed from the given mouse or
-  // touch event. For example, PointerEvent does not support ET_MOUSEWHEEL or
-  // ET_MOUSE_CAPTURE_CHANGED.
+  // Returns true if |event| is a MouseEvent or TouchEvent.

[sadrul, 2016/08/19 04:18:27]

Something more like: Returns true if a PointerEvent can be constructed from
|event|. Currently, only mouse and touch events can be converted to pointer
events.

[riajiang, 2016/08/19 16:19:39]

Done.

   static bool CanConvertFrom(const Event& event);
 
   PointerEvent(const PointerEvent& pointer_event);