Make pinch zoom work on chromeos by setting touch id correctly

ui/events/event.h

 // 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.
 
 #ifndef UI_EVENTS_EVENT_H_
 #define UI_EVENTS_EVENT_H_
 
 #include <stdint.h>
 
 #include <memory>
@@ skipping 560 matching lines @@
   // that was released.
   // NOTE: during a press and release flags() contains the complete set of
   // flags. Use this to determine the button that was pressed or released.
   int changed_button_flags() const { return changed_button_flags_; }
 
   // Updates the button that changed.
   void set_changed_button_flags(int flags) { changed_button_flags_ = flags; }
 
   // Event details common to MouseEvent and TouchEvent.
   const PointerDetails& pointer_details() const { return pointer_details_; }
-  void set_pointer_details(const PointerDetails& details) {
-    pointer_details_ = details;
-  }
+  void set_pointer_details(const PointerDetails& details);
 
  private:
   FRIEND_TEST_ALL_PREFIXES(EventTest, DoubleClickRequiresRelease);
   FRIEND_TEST_ALL_PREFIXES(EventTest, SingleClickRightLeft);
 
   // Returns the repeat count based on the previous mouse click, if it is
   // recent enough and within a small enough distance.
   static int GetRepeatCount(const MouseEvent& click_event);
 
   // Resets the last_click_event_ for unit tests.
@@ skipping 109 matching lines @@
       const gfx::Transform& inverted_root_transform) override;
 
   // Marks the event as not participating in synchronous gesture recognition.
   void DisableSynchronousHandling();
   bool synchronous_handling_disabled() const {
     return !!(result() & ER_DISABLE_SYNC_HANDLING);
   }
 
   // Event details common to MouseEvent and TouchEvent.
   const PointerDetails& pointer_details() const { return pointer_details_; }
-  void set_pointer_details(const PointerDetails& pointer_details) {
-    pointer_details_ = pointer_details;
-  }
+  void set_pointer_details(const PointerDetails& pointer_details);
 
  private:
   // Adjusts rotation_angle_ to within the acceptable range.
   void FixRotationAngle();
 
   // A unique identifier for the touch event.
   uint32_t unique_event_id_;
 
   // Clockwise angle (in degrees) of the major axis from the X axis. Must be
   // less than 180 and non-negative.
@@ skipping 314 matching lines @@
   // dispatched. This field gets a non-zero value only for gestures that are
   // released through TouchDispositionGestureFilter::SendGesture. The gesture
   // events that aren't fired directly in response to processing a touch-event
   // (e.g. timer fired ones), this id is zero. See crbug.com/618738.
   uint32_t unique_touch_event_id_;
 };
 
 }  // namespace ui
 
 #endif  // UI_EVENTS_EVENT_H_