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

ui/views/controls/tree/tree_view_views.cc

Index: ui/views/controls/tree/tree_view_views.cc
diff --git a/ui/views/controls/tree/tree_view_views.cc b/ui/views/controls/tree/tree_view_views.cc
index 92a6c2b4fa068be1bbfaa6d6f68ba200bb48c521..524b76377fd44e09ce20c361959d0954d4b85b66 100644
--- a/ui/views/controls/tree/tree_view_views.cc
+++ b/ui/views/controls/tree/tree_view_views.cc
@@ -14,7 +14,7 @@
 #include "ui/base/resource/resource_bundle.h"
 #include "ui/gfx/canvas.h"
 #include "ui/gfx/image/image.h"
-#include "ui/gfx/native_theme.h"
+#include "ui/base/native_theme/native_theme.h"
 #include "ui/gfx/skia_util.h"
 #include "ui/views/background.h"
 #include "ui/views/border.h"
@@ -81,8 +81,8 @@ View* TreeView::CreateParentIfNecessary() {
   ScrollView* scroll_view = new ScrollView;
   scroll_view->SetContents(this);
   scroll_view->set_border(Border::CreateSolidBorder(
-      1, gfx::NativeTheme::instance()->GetSystemColor(
-          gfx::NativeTheme::kColorId_UnfocusedBorderColor)));
+      1, ui::NativeTheme::instance()->GetSystemColor(
+          ui::NativeTheme::kColorId_UnfocusedBorderColor)));
   return scroll_view;
 }