Desktop Aura: Allow tab drags out of window.

ui/aura/client/window_move_client.h

Index: ui/aura/client/window_move_client.h
diff --git a/ui/aura/client/window_move_client.h b/ui/aura/client/window_move_client.h
index b6f32a0920b91456401d47ee2d027275b8494104..048e572b747ea273c21637c2839652f1f4d6de33 100644
--- a/ui/aura/client/window_move_client.h
+++ b/ui/aura/client/window_move_client.h
@@ -7,6 +7,10 @@
 
 #include "ui/aura/aura_export.h"
 
+namespace gfx {
+class Point;
+}
+
 namespace aura {
 class Window;
 namespace client {
@@ -15,8 +19,9 @@ namespace client {
 // window moving.
 class AURA_EXPORT WindowMoveClient {
  public:
-  // Starts a nested message loop for moving the window.
-  virtual void RunMoveLoop(Window* window) = 0;
+  // Starts a nested message loop for moving the window. |drag_offset| is the
+  // offset from the window origin to the cursor when the drag was started.
+  virtual void RunMoveLoop(Window* window, const gfx::Point& drag_offset) = 0;
 
   // Ends a previously started move loop.
   virtual void EndMoveLoop() = 0;