Split ios/chrome/app/startup targets to reduce dependencies.

ios/chrome/browser/BUILD.gn

 # Copyright 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.
 
 import("//build/buildflag_header.gni")
 import("//build/config/features.gni")
 import("//build/config/ios/rules.gni")
 import("//rlz/features/features.gni")
 import("//third_party/protobuf/proto_library.gni")
 
 declare_args() {
   google_test_gaia_client_id = ""
   google_test_gaia_client_secret = ""
   google_staging_api_url = ""
   google_staging_lso_url = ""
   google_test_api_url = ""
   google_test_lso_url = ""
   google_test_oauth_client_id = ""
   google_test_oauth_client_secret = ""
   google_test_oauth_url = ""
   google_test_sync_url = ""
 }
 
+source_set("chrome_paths") {
+  configs += [ "//build/config/compiler:enable_arc" ]
+  sources = [
+    "chrome_paths.h",
+    "chrome_paths.mm",
+    "chrome_paths_internal.h",
+  ]
+
+  deps = [
+    "//base",
+    "//components/gcm_driver",
+  ]
+}
+
 source_set("browser") {
   configs += [ "//build/config/compiler:enable_arc" ]
   sources = [
     "about_flags.h",
     "about_flags.mm",
     "app_startup_parameters.h",
     "app_startup_parameters.mm",
     "application_context.cc",
     "application_context.h",
     "arch_util.cc",
     "arch_util.h",
     "browser_about_rewriter.cc",
     "browser_about_rewriter.h",
     "chrome_constants.cc",
     "chrome_constants.h",
     "chrome_coordinator.h",
     "chrome_coordinator.mm",
-    "chrome_paths.h",
-    "chrome_paths.mm",
-    "chrome_paths_internal.h",
     "chrome_switches.cc",
     "chrome_switches.h",
     "chrome_url_constants.cc",
     "chrome_url_constants.h",
     "chrome_url_util.h",
     "chrome_url_util.mm",
     "crash_loop_detection_util.h",
     "crash_loop_detection_util.mm",
     "experimental_flags.h",
     "experimental_flags.mm",
@@ skipping 17 matching lines @@
     "root_coordinator.h",
     "root_coordinator.mm",
     "storekit_launcher.h",
     "tab_parenting_global_observer.cc",
     "tab_parenting_global_observer.h",
     "web_data_service_factory.cc",
     "web_data_service_factory.h",
     "xcallback_parameters.h",
     "xcallback_parameters.mm",
   ]
+
+  public_deps = [

[sdefresne, 2017/02/01 14:01:02]

nit: can you put public_deps after deps (and without blank lines for consistency
with the rest of the BUILD.gn files in //ios)?

[marq (ping after 24h), 2017/05/03 15:27:27]

Done.

+    ":chrome_paths",
+  ]
+
   deps = [
     ":google_api_keys_header",
     ":settings_resources",
     "//base",
     "//components/autofill/core/browser",
     "//components/autofill/core/common",
     "//components/dom_distiller/core",
     "//components/flags_ui",
     "//components/flags_ui:switches",
-    "//components/gcm_driver",
     "//components/handoff",
     "//components/keyed_service/core",
     "//components/keyed_service/ios",
     "//components/metrics",
     "//components/metrics_services_manager",
     "//components/net_log",
     "//components/network_session_configurator",
     "//components/ntp_tiles",
     "//components/pref_registry",
     "//components/prefs",
@@ skipping 148 matching lines @@
 
 source_set("browser_internal") {
   sources = [
     "callback_counter.h",
     "callback_counter.mm",
   ]
   deps = [
     "//base",
   ]
 }