[Mac/GN] Set up the component build.

ui/snapshot/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")
 import("//testing/test.gni")
 
 component("snapshot") {
   sources = [
     "screenshot_grabber.cc",
@@ skipping 41 matching lines @@
   }
 
   if (use_aura) {
     deps += [
       "//ui/aura",
       "//ui/compositor",
     ]
   } else {
     sources -= [ "snapshot_aura.cc" ]
   }
+
+  if (is_mac) {
+    libs = [
+      "AppKit.framework",
+      "CoreGraphics.framework",
+    ]
+  }
 }
 
 test("snapshot_unittests") {
   sources = [
     "snapshot_aura_unittest.cc",
     "snapshot_mac_unittest.mm",
     "test/run_all_unittests.cc",
   ]
 
   deps = [
@@ skipping 13 matching lines @@
     deps += [
       "//ui/aura:test_support",
       "//ui/compositor",
       "//ui/compositor:test_support",
       "//ui/wm",
     ]
   } else {
     sources -= [ "snapshot_aura_unittest.cc" ]
   }
 }