Remove abstract Clone and Cancel methods from MotionEvent

ui/events/gesture_detection/motion_event.h

Index: ui/events/gesture_detection/motion_event.h
diff --git a/ui/events/gesture_detection/motion_event.h b/ui/events/gesture_detection/motion_event.h
index 2277277aa91812ddb57c0767159817f6541fc07a..e2fdf2c06089898785a9bfe296859662ca3fb10f 100644
--- a/ui/events/gesture_detection/motion_event.h
+++ b/ui/events/gesture_detection/motion_event.h
@@ -5,6 +5,8 @@
 #ifndef UI_EVENTS_GESTURE_DETECTION_MOTION_EVENT_H_
 #define UI_EVENTS_GESTURE_DETECTION_MOTION_EVENT_H_
 
+#include <string>
+
 #include "base/memory/scoped_ptr.h"
 #include "base/time/time.h"
 #include "ui/events/gesture_detection/gesture_detection_export.h"
@@ -76,9 +78,7 @@ class GESTURE_DETECTION_EXPORT MotionEvent {
   virtual float GetHistoricalY(size_t pointer_index,
                                size_t historical_index) const;
 
-  virtual scoped_ptr<MotionEvent> Clone() const = 0;
-  virtual scoped_ptr<MotionEvent> Cancel() const = 0;
-
+  // Utility accessor methods for convenience.
   float GetX() const { return GetX(0); }
   float GetY() const { return GetY(0); }
   float GetRawX() const { return GetRawX(0); }
@@ -98,12 +98,18 @@ class GESTURE_DETECTION_EXPORT MotionEvent {
 
   // O(N) search of pointers (use sparingly!). Returns -1 if |id| nonexistent.
   int FindPointerIndexOfId(int id) const;
-};
 
-GESTURE_DETECTION_EXPORT bool operator==(const MotionEvent& lhs,
-                                         const MotionEvent& rhs);
-GESTURE_DETECTION_EXPORT bool operator!=(const MotionEvent& lhs,
-                                         const MotionEvent& rhs);
+  // Note that these methods perform shallow copies of the originating events.
+  // They guarantee only that the returned type will reflect the same
+  // data exposed by the MotionEvent interface; no guarantees are made that the
+  // underlying implementation is identical to the source implementation.
+  scoped_ptr<MotionEvent> Clone() const;
+  scoped_ptr<MotionEvent> Cancel() const;
+
+  // Note: This routine is not at all optimized and should not be used outside
+  // of testing in any production code.
+  std::string ToString() const;
+};
 
 }  // namespace ui