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

ui/native_theme/native_theme_mac.mm

 // 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.
 
 #include "ui/native_theme/native_theme_mac.h"
 
 #import <Cocoa/Cocoa.h>
 
 #include "base/basictypes.h"
 #include "base/mac/mac_util.h"
@@ skipping 108 matching lines @@
                         SkScalarRoundToInt(255.0 * components[0]),
                         SkScalarRoundToInt(255.0 * components[0]),
                         SkScalarRoundToInt(255.0 * components[0]));
 }
 
 }  // namespace
 
 namespace ui {
 
 // static
-NativeTheme* NativeTheme::instance() {
+NativeTheme* NativeTheme::GetInstanceForWeb() {
   return NativeThemeMac::instance();
 }
 
 // static
 NativeThemeMac* NativeThemeMac::instance() {
   CR_DEFINE_STATIC_LOCAL(NativeThemeMac, s_native_theme, ());
   return &s_native_theme;
 }
 
 SkColor NativeThemeMac::GetSystemColor(ColorId color_id) const {
@@ skipping 274 matching lines @@
   set_scrollbar_button_length(0);
   SetScrollbarColors(kScrollerThumbColor,
                      kScrollerThumbHoverColor,
                      kScrollerTrackGradientColors[0]);
 }
 
 NativeThemeMac::~NativeThemeMac() {
 }
 
 }  // namespace ui