Add support for rect-based event targeting in views

ui/views/view.h

Index: ui/views/view.h
diff --git a/ui/views/view.h b/ui/views/view.h
index 0935c51193f50823af22aad9b4a866f9cd8c0c8d..ce6e202966fcea1060076fd4dd71654aec5beb01 100644
--- a/ui/views/view.h
+++ b/ui/views/view.h
@@ -448,6 +448,16 @@ class VIEWS_EXPORT View : public ui::LayerDelegate,
                                    const View* target,
                                    gfx::Point* point);
 
+  // Convert |rect| from the coordinate system of |source| to the coordinate
+  // system of |target|.
+  //
+  // |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 ConvertRectToTarget(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);
 
@@ -548,12 +558,20 @@ class VIEWS_EXPORT View : public ui::LayerDelegate,
   static bool get_use_acceleration_when_possible();
 
   // Input ---------------------------------------------------------------------
-  // The points (and mouse locations) in the following functions are in the
-  // view's coordinates, except for a RootView.
+  // The points, rects, mouse locations, and touch locations in the following
+  // functions are in the view's coordinates, except for a RootView.
 
-  // Returns the deepest visible descendant that contains the specified point
-  // and supports event handling.
-  virtual View* GetEventHandlerForPoint(const gfx::Point& point);
+  // Convenience functions which calls into GetEventHandler() with
+  // a 1x1 rect centered at |point|.
+  View* GetEventHandlerForPoint(const gfx::Point& point);
+
+  // If point-based targeting should be used, return the deepest visible
+  // descendant that contains the center point of |rect|.
+  // If rect-based targeting (i.e., fuzzing) should be used, return the
+  // closest visible descendant having at least kViewsFuzzingOverlap of
+  // its area covered by |rect|. If no such descendant exists, return the
+  // deepest visible descendant that contains the center point of |rect|.
+  virtual View* GetEventHandlerForRect(const gfx::Rect& rect);
 
   // Returns the deepest visible descendant that contains the specified point
   // and supports tooltips. If the view does not contain the point, returns
@@ -959,6 +977,22 @@ class VIEWS_EXPORT View : public ui::LayerDelegate,
   virtual int GetLineScrollIncrement(ScrollView* scroll_view,
                                      bool is_horizontal, bool is_positive);
 
+  // Views fuzzing -------------------------------------------------------------
+  // Helper functions used by the views fuzzing algorithm.
+
+  // Returns true if |rect| is 1x1.
+  static bool UsePointBasedTargeting(const gfx::Rect& rect);
+
+  // Returns the percentage of |rect_1|'s area that is covered by |rect_2|.
+  static float PercentCoveredBy(const gfx::Rect& rect_1,
+                                const gfx::Rect& rect_2);
+
+  // Returns the square of the distance from |point| to the center line of
+  // |target_rect|. The center line of a rectangle is obtained by repeatedly
+  // stripping away 1px borders around the rectangle until a line remains.
+  static int DistanceSquaredFromCenterLineToPoint(const gfx::Point& point,
+                                                 const gfx::Rect& target_rect);
+
  protected:
   // Used to track a drag. RootView passes this into
   // ProcessMousePressed/Dragged.
@@ -1314,10 +1348,21 @@ class VIEWS_EXPORT View : public ui::LayerDelegate,
 
   // Convert a point in the ancestor's coordinate system to the view's
   // coordinate system using necessary transformations. Returns whether the
-  // point was successfully from the ancestor's coordinate system to the view's
-  // coordinate system.
+  // point was successfully converted from the ancestor's coordinate system
+  // to the view's coordinate system.
   bool ConvertPointFromAncestor(const View* ancestor, gfx::Point* point) const;
 
+  // Convert a rect in the view's coordinate to an ancestor view's coordinate
+  // system using necessary transformations. Returns whether the rect was
+  // successfully converted to the ancestor's coordinate system.
+  bool ConvertRectForAncestor(const View* ancestor, gfx::Rect* rect) const;
+
+  // Convert a rect in the ancestor's coordinate system to the view's
+  // coordinate system using necessary transformations. Returns whether the
+  // rect was successfully converted from the ancestor's coordinate system
+  // to the view's coordinate system.
+  bool ConvertRectFromAncestor(const View* ancestor, gfx::Rect* rect) const;
+
   // Accelerated painting ------------------------------------------------------
 
   // Creates the layer and related fields for this view.