Allow the cursor to warp even when a window is dragged

ash/shell.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 ASH_SHELL_H_
 #define ASH_SHELL_H_
 
 #include <utility>
 #include <vector>
 
@@ skipping 160 matching lines @@
   static aura::RootWindow* GetRootWindowAt(const gfx::Point& point);
 
   // Returns the RootWindow that shares the most area with |rect| in
   // the virtual scren coordinates.
   static aura::RootWindow* GetRootWindowMatching(const gfx::Rect& rect);
 
   // Returns all root windows. In non extended desktop mode, this
   // returns the primary root window only.
   static RootWindowList GetAllRootWindows();
 
+  // If |location_in_root| is inside |root_window|'s bounds, just returns a pair
+  // of |root_window| and |location_in_root| as-is. If |location_in_root| is
+  // outside the |root_window|, the function tries to find another root window
+  // where the cursor is on and returns a pair of the window and location in the
+  // window's coordinates.
+  static std::pair<aura::RootWindow*, gfx::Point> NormalizeLocationInDragEvent(
+    aura::RootWindow* root_window,
+    gfx::Point location_in_root);
+
   static aura::Window* GetContainer(aura::RootWindow* root_window,
                                     int container_id);
 
   // Returns the list of containers that match |container_id| in
   // all root windows.
   static std::vector<aura::Window*> GetAllContainers(int container_id);
 
   void set_active_root_window(aura::RootWindow* active_root_window) {
     active_root_window_ = active_root_window;
   }
@@ skipping 295 matching lines @@
 
   // Used by ash/shell.
   content::BrowserContext* browser_context_;
 
   DISALLOW_COPY_AND_ASSIGN(Shell);
 };
 
 }  // namespace ash
 
 #endif  // ASH_SHELL_H_