[Mac/GN] Move the bundle ID and creator code into the BRANDING file, and use it.

chrome/app_shim/BUILD.gn

Index: chrome/app_shim/BUILD.gn
diff --git a/chrome/app_shim/BUILD.gn b/chrome/app_shim/BUILD.gn
index 141bf72bef0ac601c376752a56e564b9163001a4..5171b51f9b5ab3c950590a67a923c90669db1bc0 100644
--- a/chrome/app_shim/BUILD.gn
+++ b/chrome/app_shim/BUILD.gn
@@ -3,6 +3,7 @@
 # found in the LICENSE file.
 
 import("//build/config/mac/rules.gni")
+import("//build/util/branding.gni")
 
 # This is the part of the shim process compiled into Chrome. It runs only
 # in the shim process, after the shim finds and loads the Chrome
@@ -22,6 +23,7 @@ mac_app_bundle("app_mode_loader") {
   extra_configs = [ "//build/config/compiler:wexit_time_destructors" ]
 
   info_plist = "app_mode-Info.plist"
+  extra_substitutions = [ "APP_MODE_APP_BUNDLE_ID=$chrome_mac_bundle_id.app.@APP_MODE_SHORTCUT_ID@" ]
 
   sources = [
     "app_mode_loader_mac.mm",
@@ -31,8 +33,6 @@ mac_app_bundle("app_mode_loader") {
     "//chrome/common:app_mode_app_support",
   ]
 
-  # TODO(rsesek): extra_substitutions = [ APP_MODE_APP_BUNDLE_ID ... ]
-
   libs = [
     "CoreFoundation.framework",
     "Foundation.framework",