Make skia::GetNativeDrawingContext Windows-only

skia/BUILD.gn

 # 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.
 
 import("//build/config/features.gni")
 import("//build/config/ui.gni")
 import("//build/config/sanitizers/sanitizers.gni")
 import("//printing/features/features.gni")
 import("//testing/test.gni")
 import("//third_party/skia/gn/shared_sources.gni")
@@ skipping 625 matching lines @@
     ":skia_library_config",
     "//build/config/compiler:no_chromium_code",
   ]
 
   visibility = [ ":skia" ]
 }
 
 test("skia_unittests") {
   sources = [
     "ext/analysis_canvas_unittest.cc",
-    "ext/bitmap_platform_device_mac_unittest.cc",
     "ext/convolver_unittest.cc",
     "ext/image_operations_unittest.cc",
     "ext/platform_canvas_unittest.cc",
     "ext/recursive_gaussian_convolution_unittest.cc",
     "ext/skia_memory_dump_provider_unittest.cc",
     "ext/skia_utils_ios_unittest.mm",
     "ext/skia_utils_mac_unittest.mm",
   ]
 
-  if (!is_win && !is_mac && !use_cairo) {
+  if (!is_win) {
     sources -= [ "ext/platform_canvas_unittest.cc" ]
   }
 
   deps = [
     ":skia",
     "//base",
     "//mojo/edk/test:run_all_unittests",
     "//testing/gtest",
     "//ui/gfx",
     "//ui/gfx/geometry",
@@ skipping 38 matching lines @@
 
     deps = [
       ":skia",
       "//base",
       "//base/test:test_support",
       "//build/config/sanitizers:deps",
       "//build/win:default_exe_manifest",
     ]
   }
 }