Make pinch zoom work on chromeos by setting touch id correctly

ui/events/event.cc

Index: ui/events/event.cc
diff --git a/ui/events/event.cc b/ui/events/event.cc
index f3659017ddd5736d050a229311e3adf0cf0940c6..75db09c30d66362ab580fa7325cfde0bc1d4f937 100644
--- a/ui/events/event.cc
+++ b/ui/events/event.cc
@@ -762,6 +762,16 @@ void MouseEvent::SetClickCount(int click_count) {
   set_flags(f);
 }
 
+void MouseEvent::set_pointer_details(const PointerDetails& details) {
+  if (details.pointer_type == EventPointerType::POINTER_TYPE_TOUCH) {

[sadrul, 2017/03/01 15:35:59]

For MouseEvent, when do we set pointer_type to TYPE_TOUCH?

[lanwei, 2017/03/01 20:12:22]

So far, I have not seen. I am afraid it may be set from a touch type in the
future.

+    DCHECK(pointer_details_.id == 0 || details.id != 0);
+  } else {
+    DCHECK(pointer_details_.id == PointerEvent::kMousePointerId ||
+           details.id != PointerEvent::kMousePointerId);
+  }
+  pointer_details_ = details;
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 // MouseWheelEvent
 
@@ -972,6 +982,16 @@ void TouchEvent::FixRotationAngle() {
     rotation_angle_ -= 180;
 }
 
+void TouchEvent::set_pointer_details(const PointerDetails& pointer_details) {
+  if (pointer_details.pointer_type == EventPointerType::POINTER_TYPE_TOUCH) {
+    DCHECK(pointer_details_.id == 0 || pointer_details.id != 0);
+  } else {
+    DCHECK(pointer_details_.id == PointerEvent::kMousePointerId ||
+           pointer_details.id != PointerEvent::kMousePointerId);

[sadrul, 2017/03/01 15:35:59]

When do we create a TouchEvent when pointer_type is not TYPE_TOUCH?

[lanwei, 2017/03/01 20:12:22]

On Kevin (chromebook) device, the pointer type is pen, but it is sent as a touch
event.

+  }
+  pointer_details_ = pointer_details;
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 // PointerEvent