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

ui/native_theme/native_theme_mac_unittest.cc

 // Copyright 2014 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"
 
 #include "base/mac/mac_util.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace ui {
 
 // Test to ensure any system colors that are looked up by name exist on all Mac
 // platforms Chrome supports, and that their colorspace and component count is
 // sane.
 TEST(NativeThemeMacTest, SystemColorsExist) {
-  NativeTheme* native_theme = NativeTheme::instance();
+  NativeTheme* native_theme = NativeThemeMac::instance();
   ASSERT_TRUE(native_theme);
   for (int i = 0; i < NativeTheme::kColorId_NumColors; ++i) {
     // While 0 is a valid color, no system color should be fully transparent.
     // This is also to probe for CHECKs.
     EXPECT_NE(
         static_cast<SkColor>(0),
         native_theme->GetSystemColor(static_cast<NativeTheme::ColorId>(i)))
             << "GetSystemColor() unexpectedly gave a fully transparent color.";
   }
 }
 
 // Spot-check some system colours that can't be changed through System
 // Preferences.
 TEST(NativeThemeMacTest, SystemColorSpotChecks) {
-  NativeTheme* native_theme = NativeTheme::instance();
+  NativeTheme* native_theme = NativeThemeMac::instance();
   const SkColor kWindowColorCatsMavericks = SkColorSetARGB(255, 232, 232, 232);
   const SkColor kWindowColorYosemite = SkColorSetARGB(255, 236, 236, 236);
   SkColor dialogColor =
       native_theme->GetSystemColor(NativeTheme::kColorId_WindowBackground);
   if (base::mac::IsOSYosemiteOrLater())
     EXPECT_EQ(dialogColor, kWindowColorYosemite);
   else
     EXPECT_EQ(dialogColor, kWindowColorCatsMavericks);
 }
 
 }  // namespace ui