Make component build Chrome link.

google_apis/gcm/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("//third_party/protobuf/proto_library.gni")
 
 component("gcm") {
   sources = [
     "base/mcs_message.cc",
     "base/mcs_message.h",
@@ skipping 46 matching lines @@
   forward_dependent_configs_from = [ ":proto" ]
 }
 
 proto_library("proto") {
   visibility = [ ":*" ]
   sources = [
     "protocol/android_checkin.proto",
     "protocol/checkin.proto",
     "protocol/mcs.proto",
   ]
+
+  cc_generator_options = "dllexport_decl=GCM_EXPORT:"
+  cc_include = "google_apis/gcm/base/gcm_export.h"
+  defines = [ "GCM_IMPLEMENTATION" ]
 }
 
 static_library("test_support") {
   testonly = true
   sources = [
     "base/fake_encryptor.cc",
     "base/fake_encryptor.h",
     "engine/fake_connection_factory.cc",
     "engine/fake_connection_factory.h",
     "engine/fake_connection_handler.cc",
@@ skipping 48 matching lines @@
   deps = [
     ":proto",
     ":test_support",
     "//base",
     "//base/test:run_all_unittests",
     "//net",
     "//net:test_support",
     "//testing/gtest",
   ]
 }