Add variables to simplify code signing on iOS.

build/config/ios/ios_sdk.gni

Index: build/config/ios/ios_sdk.gni
diff --git a/build/config/ios/ios_sdk.gni b/build/config/ios/ios_sdk.gni
index 0a3cded59cf1661546695f3a589ae8ad7057f0e4..78a84dec923e2df194694af458068d6cb429c977 100644
--- a/build/config/ios/ios_sdk.gni
+++ b/build/config/ios/ios_sdk.gni
@@ -25,6 +25,17 @@ declare_args() {
   ios_enable_code_signing = true
   ios_code_signing_identity = ""
 
+  # Prefix for CFBundleIdentifier property of iOS bundles (correspond to the
+  # "Organization Identifier" in Xcode). Code signing will fail if no mobile
+  # provisioning for the selected code signing identify support that prefix.
+  ios_app_bundle_id_prefix = "org.chromium"
+
+  # If true, then allow using Xcode to automatically manage certificates. This
+  # requires loading a separate Xcode project and enable automatically managed
+  # certificates. When true, all test application will use the same bundle id
+  # to avoid running out of certificates if using a free account.
+  ios_automatically_manage_certs = true
+
   # If non-empty, this list must contain valid cpu architecture, and the final
   # build will be a multi-architecture build (aka fat build) supporting the
   # main $target_cpu architecture and all of $additional_target_cpus.