Move WindowImpl to gfx so I can use it there for canvas unit tests....

gfx/window_impl.cc

Index: gfx/window_impl.cc
===================================================================
--- gfx/window_impl.cc	(revision 51425)
+++ gfx/window_impl.cc	(working copy)
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "app/win/window_impl.h"
+#include "gfx/window_impl.h"
 
 #include <list>
 
@@ -10,7 +10,7 @@
 #include "base/string_util.h"
 #include "base/win_util.h"
 
-namespace app {
+namespace gfx {
 
 static const DWORD kWindowDefaultChildStyle =
     WS_CHILD | WS_VISIBLE | WS_CLIPCHILDREN | WS_CLIPSIBLINGS;
@@ -223,4 +223,4 @@
   return name;
 }
 
-}  // namespace app
+}  // namespace gfx