Set toolbar padding to something appropriate for Metro icons.

ui/base/scale.h

+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef UI_BASE_SCALE_H_
+#define UI_BASE_SCALE_H_
+#pragma once
+
+#include "build/build_config.h"
+#include "ui/base/ui_export.h"
+
+namespace ui {
+
+enum DisplayScale {
+  DS_ASH,
+  DS_DESKTOP_100,
+#if defined(OS_WIN)
+  DS_DESKTOP_200,
+  DS_METRO_100,
+  DS_METRO_140,
+  DS_METRO_180,
+#endif  // defined(OS_WIN)
+};
+
+// Returns the display scale in use for themes.

[sail, 2012/04/18 16:44:14]

can you expand this comment a bit more? What's the difference between a theme
scale and a UI scale. For example, when would I use theme and when would I use
UI?

[Jói, 2012/04/18 17:06:31]

I've added a TODO on the second function that expands on this a bit.  Basically
I was making sure to leave the existing functionality, which was that for the UI
resources, we don't currently care whether Metro is enabled, but we do care
whether high-DPI is enabled.  I was thinking we would probably want to unify all
of this stuff as much as possible.

+UI_EXPORT const DisplayScale GetThemeScale();
+
+// Returns the display scale in use for UI.
+UI_EXPORT const DisplayScale GetUIScale();
+
+}  // namespace ui
+
+#endif  // UI_BASE_SCALE_H_