Add support for rect-based event targeting in views

ui/views/view.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_VIEWS_VIEW_H_
 #define UI_VIEWS_VIEW_H_
 
 #include <algorithm>
 #include <map>
 #include <set>
@@ skipping 541 matching lines @@
     flip_canvas_on_paint_for_rtl_ui_ = enable;
   }
 
   // Accelerated painting ------------------------------------------------------
 
   // Enable/Disable accelerated compositing.
   static void set_use_acceleration_when_possible(bool use);
   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 kRectTargetOverlap 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
   // NULL.
   virtual View* GetTooltipHandlerForPoint(const gfx::Point& point);
 
   // 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
   // lifetime may vary from platform to platform. On Windows and Aura,
@@ skipping 533 matching lines @@
   // This reorders the immediate children of |*parent_layer| to match the
   // order of the view tree. Child layers which are owned by a view are
   // reordered so that they are below any child layers not owned by a view.
   // Widget::ReorderNativeViews() should be called to reorder any child layers
   // with an associated view. Widget::ReorderNativeViews() may reorder layers
   // below layers owned by a view.
   virtual void ReorderChildLayers(ui::Layer* parent_layer);
 
   // Input ---------------------------------------------------------------------
 
+  // Specifies the source of the region used in a hit test.
+  // HIT_TEST_SOURCE_MOUSE indicates the hit test is being performed with a
+  // single point and HIT_TEST_SOURCE_TOUCH indicates the hit test is being
+  // performed with a rect larger than a single point. This value can be used,
+  // for example, to add extra padding or change the shape of the hit test mask.
+  enum HitTestSource {
+    HIT_TEST_SOURCE_MOUSE,
+    HIT_TEST_SOURCE_TOUCH
+  };
+
   // Called by HitTestRect() to see if this View has a custom hit test mask. If
   // the return value is true, GetHitTestMask() will be called to obtain the
   // mask. Default value is false, in which case the View will hit-test against
   // its bounds.
   virtual bool HasHitTestMask() const;
 
   // Called by HitTestRect() to retrieve a mask for hit-testing against.
   // Subclasses override to provide custom shaped hit test regions.
-  virtual void GetHitTestMask(gfx::Path* mask) const;
+  virtual void GetHitTestMask(gfx::Path* mask,
+      HitTestSource source = HIT_TEST_SOURCE_MOUSE) const;
 
   virtual DragInfo* GetDragInfo();
 
   // Focus ---------------------------------------------------------------------
 
   // Override to be notified when focus has changed either to or from this View.
   virtual void OnFocus();
   virtual void OnBlur();
 
   // Handle view focus/blur events for this view.
@@ skipping 412 matching lines @@
   // Belongs to this view, but it's reference-counted on some platforms
   // so we can't use a scoped_ptr. It's dereferenced in the destructor.
   NativeViewAccessibility* native_view_accessibility_;
 
   DISALLOW_COPY_AND_ASSIGN(View);
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_VIEW_H_