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

ui/views/BUILD.gn

 # 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.
 
 import("//build/config/features.gni")
 import("//build/config/ui.gni")
 import("//testing/test.gni")
 
 gypi_values = exec_script("//build/gypi_to_gn.py",
                           [ rebase_path("views.gyp") ],
@@ skipping 16 matching lines @@
   ]
 
   defines = [ "VIEWS_IMPLEMENTATION" ]
 
   deps = [
     "//base:i18n",
     "//base/third_party/dynamic_annotations",
     "//skia",
     "//third_party/icu",
     "//ui/accessibility",
-    "//ui/native_theme",
     "//ui/resources",
     "//ui/strings",
     "//ui/views/resources",
     "//url",
   ]
 
   public_deps = [
     "//base",
     "//ui/accessibility:ax_gen",
     "//ui/base",
     "//ui/base/ime",
     "//ui/compositor",
     "//ui/events",
     "//ui/events:events_base",
     "//ui/events/platform",
     "//ui/gfx",
     "//ui/gfx/geometry",
+    "//ui/native_theme",
     "//ui/views/resources",
   ]
 
   if (use_x11 && !is_chromeos) {
     deps += [ "//ui/display/util" ]
   }
   if (is_linux && !is_chromeos) {
     sources -= [ "window/window_button_order_provider.cc" ]
     deps += [ "//ui/shell_dialogs" ]
   } else {
@@ skipping 233 matching lines @@
       "//skia",
       "//testing/gtest",
       "//ui/base:test_support",
       "//ui/compositor",
       "//ui/resources",
       "//ui/resources:ui_test_pak",
       "//ui/strings",
     ]
   }
 }