Change name of NativeTheme::instance() to make it clear it's web only.

ui/native_theme/native_theme_mac.h

 // Copyright (c) 2013 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_NATIVE_THEME_NATIVE_THEME_MAC_H_
 #define UI_NATIVE_THEME_NATIVE_THEME_MAC_H_
 
 #include "ui/native_theme/native_theme_base.h"
 #include "ui/native_theme/native_theme_export.h"
 
 namespace ui {
 
 // Mac implementation of native theme support.
-class NativeThemeMac : public NativeThemeBase {
+class NATIVE_THEME_EXPORT NativeThemeMac : public NativeThemeBase {
  public:
   static NativeThemeMac* instance();
 
   // Overridden from NativeTheme:
   SkColor GetSystemColor(ColorId color_id) const override;
 
   // Overridden from NativeThemeBase:
   void PaintScrollbarTrack(SkCanvas* canvas,
                            Part part,
                            State state,
@@ skipping 19 matching lines @@
  private:
   NativeThemeMac();
   ~NativeThemeMac() override;
 
   DISALLOW_COPY_AND_ASSIGN(NativeThemeMac);
 };
 
 }  // namespace ui
 
 #endif  // UI_NATIVE_THEME_NATIVE_THEME_MAC_H_