ui: Move NativeTheme files into ui/base/native_theme/ directory.

ui/base/native_theme/native_theme_aura.cc

Index: ui/base/native_theme/native_theme_aura.cc
diff --git a/ui/gfx/native_theme_aura.cc b/ui/base/native_theme/native_theme_aura.cc
similarity index 99%
rename from ui/gfx/native_theme_aura.cc
rename to ui/base/native_theme/native_theme_aura.cc
index b3be18b33987925726f2652ac2b2e24960457926..56336c0fd926d58b5883799b3f33e6ee69d460e1 100644
--- a/ui/gfx/native_theme_aura.cc
+++ b/ui/base/native_theme/native_theme_aura.cc
@@ -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 "ui/gfx/native_theme_aura.h"
+#include "ui/base/native_theme/native_theme_aura.h"
 
 #include "base/logging.h"
 #include "grit/gfx_resources.h"
@@ -49,7 +49,7 @@ const SkColor kTextfieldSelectionColor =
 
 }  // namespace
 
-namespace gfx {
+namespace ui {
 
 // static
 const NativeTheme* NativeTheme::instance() {
@@ -292,4 +292,4 @@ void NativeThemeAura::PaintScrollbarThumb(SkCanvas* canvas,
   }
 }
 
-}  // namespace gfx
+}  // namespace ui