Make GN header checker more lenient about toolchains.

base/memory/BUILD.gn

 # Copyright (c) 2015 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.
 
 source_set("memory") {
   sources = [
     "aligned_memory.cc",
     "aligned_memory.h",
     "discardable_memory.cc",
     "discardable_memory.h",
@@ skipping 34 matching lines @@
       "discardable_memory_allocator.cc",
       "discardable_memory_allocator.h",
       "discardable_shared_memory.cc",
       "discardable_shared_memory.h",
       "shared_memory_posix.cc",
     ]
   } else {
     sources -= [ "shared_memory_nacl.cc" ]
   }
 
+  if (is_android) {
+    deps = [
+      "//third_party/ashmem",
+    ]
+  }
+
   configs += [ "//base:base_implementation" ]
 
   visibility = [ "//base/*" ]
 }