Make GN build work on Mac again.

ui/gfx/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/ui.gni")
 if (is_android) {
   import("//build/config/android/config.gni")
 }
 
+# Several targets want to include this header file, and some of them are
+# child dependencies of "gfx". Therefore, we separate it out here so multiple
+# targets can all have a dependency for header checking purposes without
+# creating circular dependencies.
+source_set("gfx_export") {
+  sources = [
+    "gfx_export.h",
+  ]
+}
+
 component("gfx") {
   sources = [
     "android/device_display_info.cc",
     "android/device_display_info.h",
     "android/gfx_jni_registrar.cc",
     "android/gfx_jni_registrar.h",
     "android/java_bitmap.cc",
     "android/java_bitmap.h",
     "android/scroller.cc",
     "android/scroller.h",
@@ skipping 57 matching lines @@
     "font_list_impl.cc",
     "font_list_impl.h",
     "font_render_params_android.cc",
     "font_render_params_linux.cc",
     "font_render_params_linux.h",
     "font_smoothing_win.cc",
     "font_smoothing_win.h",
     "frame_time.h",
     "gdi_util.cc",
     "gdi_util.h",
-    "gfx_export.h",
     "gfx_paths.cc",
     "gfx_paths.h",
     "gpu_memory_buffer.cc",
     "gpu_memory_buffer.h",
     "icon_util.cc",
     "icon_util.h",
     "image/canvas_image_source.cc",
     "image/canvas_image_source.h",
     "image/image.cc",
     "image/image.h",
@@ skipping 130 matching lines @@
     "win/scoped_set_map_mode.h",
     "win/singleton_hwnd.cc",
     "win/singleton_hwnd.h",
     "win/window_impl.cc",
     "win/window_impl.h",
   ]
 
   defines = [ "GFX_IMPLEMENTATION" ]
 
   deps = [
+    ":gfx_export",
     "//base",
     "//base:i18n",
     "//base:base_static",
     "//base/third_party/dynamic_annotations",
     "//skia",
     "//third_party/icu:icui18n",
     "//third_party/icu:icuuc",
     "//third_party/libpng",
     "//third_party/zlib",
     "//ui/gfx/geometry",
@@ skipping 134 matching lines @@
 source_set("gfx_test_support") {
   sources = [
     "test/gfx_util.cc",
     "test/gfx_util.h",
     "test/ui_cocoa_test_helper.h",
     "test/ui_cocoa_test_helper.mm",
   ]
 
   deps = [
     "//base",
+    "//base/test:test_support",
     "//skia",
     "//testing/gtest",
   ]
 
   if (is_ios) {
     # The cocoa files don't apply to iOS.
     sources -= [
       "test/ui_cocoa_test_helper.h",
       "test/ui_cocoa_test_helper.mm",
     ]
@@ skipping 38 matching lines @@
       "x/x11_atom_cache.h",
       "x/x11_error_tracker.cc",
       "x/x11_error_tracker.h",
       "x/x11_types.cc",
       "x/x11_types.h",
     ]
 
     configs += [ "//build/config/linux:x11" ]
   }
 }