remove duplicate atk GN config

content/browser/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("//content/browser/browser.gni")
 import("//media/media_options.gni")
 import("//tools/ipc_fuzzer/ipc_fuzzer.gni")
 
@@ skipping 259 matching lines @@
       sources -= [ "renderer_host/pepper/pepper_truetype_font_list_pango.cc" ]
     }
   }
 
   if (use_atk) {
     sources +=
         rebase_path(content_browser_gypi_values.auralinux_browser_sources,
                     ".",
                     "//content")
 
-    configs += [
-      "//build/config/linux/atk",
-      "//build/config/linux/atk:warnings",
-    ]
+    configs += [ "//build/config/linux/atk" ]
 
     if (use_gconf) {
       configs += [ "//build/config/linux/gconf" ]
     }
 
     if (use_glib) {
       configs += [ "//build/config/linux:glib" ]
     }
   }
 
@@ skipping 214 matching lines @@
   if (!is_component_build) {
     public_deps = [
       ":browser",
     ]
   } else {
     public_deps = [
       "//third_party/leveldatabase",
     ]
   }
 }