Add gesture target fuzzing to views

ui/views/view.h

Index: ui/views/view.h
diff --git a/ui/views/view.h b/ui/views/view.h
index 9482cefa86b0b5b57bc7dc12250bbc8602425846..83efc7b7d4e43cd75eb2afb46f77e73149fc7ab7 100644
--- a/ui/views/view.h
+++ b/ui/views/view.h
@@ -410,6 +410,15 @@ class VIEWS_EXPORT View : public ui::LayerDelegate,
                                  const View* target,
                                  gfx::Point* point);
 
+  // Convert a rect from the coordinate system of one View to another.
+  //
+  // |source| and |target| must be in the same widget, but doesn't need to be in
+  // the same view hierarchy.
+  // |source| can be NULL in which case it means the screen coordinate system.
+  static void ConvertRectToView(const View* source,
+                                const View* target,
+                                gfx::Rect* rect);
+
   // Convert a point from a View's coordinate system to that of its Widget.
   static void ConvertPointToWidget(const View* src, gfx::Point* point);
 
@@ -500,8 +509,17 @@ class VIEWS_EXPORT View : public ui::LayerDelegate,
   // view's coordinates, except for a RootView.
 
   // Returns the deepest visible descendant that contains the specified point.
+  // Note that if you are overriding GetEventHandlerForPoint, you will likely
+  // also want to override GetEventHandlerForRect.
   virtual View* GetEventHandlerForPoint(const gfx::Point& point);
 
+  // Considers the bounding rectangles of all leaf descendant views that have
+  // at least views::kFuzzingOverlapPercentage of their area covered by
+  // |rect|. Among these rectangles, choose one that is closest to the center
+  // line of |rect| and return its corresponding View. If there are no such
+  // rectangles, NULL is returned.
+  virtual View* GetEventHandlerForRect(const gfx::Rect& rect);
+
   // Return the cursor that should be used for this view or the default cursor.
   // The event location is in the receiver's coordinate system. The caller is
   // responsible for managing the lifetime of the returned object, though that