Move a bunch of windows stuff from ui/base/win to ui/gfx/win

ui/base/win/hidden_window.cc

Index: ui/base/win/hidden_window.cc
diff --git a/ui/base/win/hidden_window.cc b/ui/base/win/hidden_window.cc
index fb4f4836b24b2fd6586235f4b3610dbcb5bed19f..3b21519597ca8c53a60d6b42ea747c9192238404 100644
--- a/ui/base/win/hidden_window.cc
+++ b/ui/base/win/hidden_window.cc
@@ -4,7 +4,7 @@
 
 #include "ui/base/win/hidden_window.h"
 
-#include "ui/base/win/window_impl.h"
+#include "ui/gfx/win/window_impl.h"
 
 namespace ui {
 
@@ -21,7 +21,7 @@ namespace {
 // window that interact poorly with us.
 //
 // See: http://crbug.com/16476
-class TempParent : public ui::WindowImpl {
+class TempParent : public gfx::WindowImpl {
  public:
   static TempParent* Get() {
     static TempParent* g_temp_parent;