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..8ebf5fc25b0dbfb6ed43ff0e09ec38e38f1b7322 100644
--- a/ui/events/event.cc
+++ b/ui/events/event.cc
@@ -762,6 +762,15 @@ void MouseEvent::SetClickCount(int click_count) {
   set_flags(f);
 }
 
+void MouseEvent::set_pointer_details(const PointerDetails& details) {
+  DCHECK_NE(EventPointerType::POINTER_TYPE_TOUCH,
+            pointer_details_.pointer_type);
+  DCHECK_NE(EventPointerType::POINTER_TYPE_TOUCH, details.pointer_type);
+  DCHECK(pointer_details_.id == PointerEvent::kMousePointerId ||
+         details.id != PointerEvent::kMousePointerId);
+  pointer_details_ = details;
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 // MouseWheelEvent
 
@@ -972,6 +981,11 @@ void TouchEvent::FixRotationAngle() {
     rotation_angle_ -= 180;
 }
 
+void TouchEvent::set_pointer_details(const PointerDetails& pointer_details) {
+  DCHECK_EQ(pointer_details_.id, pointer_details.id);
+  pointer_details_ = pointer_details;
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 // PointerEvent