Add tests for drag and drop for Linux Aura

ui/views/widget/desktop_aura/desktop_drag_drop_client_aurax11.h

Index: ui/views/widget/desktop_aura/desktop_drag_drop_client_aurax11.h
diff --git a/ui/views/widget/desktop_aura/desktop_drag_drop_client_aurax11.h b/ui/views/widget/desktop_aura/desktop_drag_drop_client_aurax11.h
index d4092489154ac5c4c79764bf35918fd3ddabb141..30f3aa022e17c6de4583a5273dffd4c6fba8fcba 100644
--- a/ui/views/widget/desktop_aura/desktop_drag_drop_client_aurax11.h
+++ b/ui/views/widget/desktop_aura/desktop_drag_drop_client_aurax11.h
@@ -97,6 +97,17 @@ class VIEWS_EXPORT DesktopDragDropClientAuraX11
   virtual void OnMouseReleased() OVERRIDE;
   virtual void OnMoveLoopEnded() OVERRIDE;
 
+ protected:
+  // The following methods are virtual for the sake of testing.
+
+  // Finds the topmost X11 window at |screen_point| and returns it if it is
+  // Xdnd aware. Returns NULL otherwise.
+  virtual ::Window FindWindowFor(const gfx::Point& screen_point);
+
+  // Sends |xev| to |xid|, optionally short circuiting the round trip to the X
+  // server.
+  virtual void SendXClientEvent(::Window xid, XEvent* xev);
+
  private:
   enum SourceState {
     // |source_current_window_| will receive a drop once we receive an
@@ -166,10 +177,6 @@ class VIEWS_EXPORT DesktopDragDropClientAuraX11
                         unsigned long event_time);
   void SendXdndDrop(::Window dest_window);
 
-  // Sends |xev| to |xid|, optionally short circuiting the round trip to the X
-  // server.
-  void SendXClientEvent(::Window xid, XEvent* xev);
-
   // A nested message loop that notifies this object of events through the
   // X11WholeScreenMoveLoopDelegate interface.
   X11WholeScreenMoveLoop move_loop_;