[ios][mac] Prefer invoker extra_substitutions to template ones

The plist substitutions are evaluated in order they are passed on
the command line. The substitutions passed by the invoker should
have priority over those defined in the template (otherwise there
would be no way to override the substitutions from a template).
This mean that if the same `key=value` is defined multiple time on
the command-line, the last pair will be used by the script.

To give the preference to the substitutions defined by the invoker,
do not use the `forward_variable_from(invoker, ...)`. Instead set
the value in the template, and if defined in the invoker, append
them.

Bug: 1257954
Change-Id: I19bed9a1424f6e7c0394fd437381fc2067c97ace
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3211733
Reviewed-by: Olivier Robin <olivierrobin@chromium.org>
Commit-Queue: Olivier Robin <olivierrobin@chromium.org>
Commit-Queue: Sylvain Defresne <sdefresne@chromium.org>
Auto-Submit: Sylvain Defresne <sdefresne@chromium.org>
Cr-Commit-Position: refs/heads/main@{#929648}

build/config/ios/rules.gni

@@ -533,11 +533,7 @@ template("ios_info_plist") {
 
   apple_info_plist(target_name) {
     format = "binary1"
-    extra_substitutions = []
-    if (defined(invoker.extra_substitutions)) {
-      extra_substitutions = invoker.extra_substitutions
-    }
-    extra_substitutions += [
+    extra_substitutions = [
       "IOS_BUNDLE_ID_PREFIX=$ios_app_bundle_id_prefix",
       "IOS_PLATFORM_BUILD=$ios_platform_build",
       "IOS_PLATFORM_NAME=$ios_sdk_name",
@@ -550,6 +546,9 @@ template("ios_info_plist") {
       "XCODE_BUILD=$xcode_build",
       "XCODE_VERSION=$xcode_version",
     ]
+    if (defined(invoker.extra_substitutions)) {
+      extra_substitutions += invoker.extra_substitutions
+    }
     plist_templates = [
       "//build/config/ios/BuildInfo.plist",
       _info_plist,
@@ -830,18 +829,16 @@ template("ios_app_bundle") {
     ios_info_plist(_generate_info_plist) {
       forward_variables_from(invoker,
                              [
-                               "extra_substitutions",
                                "info_plist",
                                "info_plist_target",
                              ])
 
       executable_name = _output_name
 
-      if (!defined(extra_substitutions)) {
-        extra_substitutions = []
+      extra_substitutions = [ "BUNDLE_IDENTIFIER=$_bundle_identifier" ]
+      if (defined(invoker.extra_substitutions)) {
+        extra_substitutions += invoker.extra_substitutions
       }
-
-      extra_substitutions += [ "BUNDLE_IDENTIFIER=$_bundle_identifier" ]
     }
 
     if (!is_fat_secondary_toolchain) {
@@ -1557,16 +1554,14 @@ template("ios_framework_bundle") {
       executable_name = _output_name
       forward_variables_from(invoker,
                              [
-                               "extra_substitutions",
                                "info_plist",
                                "info_plist_target",
                              ])
 
-      if (!defined(extra_substitutions)) {
-        extra_substitutions = []
+      extra_substitutions = [ "BUNDLE_IDENTIFIER=$_bundle_identifier" ]
+      if (defined(invoker.extra_substitutions)) {
+        extra_substitutions += invoker.extra_substitutions
       }
-
-      extra_substitutions += [ "BUNDLE_IDENTIFIER=$_bundle_identifier" ]
     }
 
     bundle_data(_info_plist_bundle) {

build/config/mac/rules.gni

@@ -40,18 +40,17 @@ template("mac_info_plist") {
 
   apple_info_plist(target_name) {
     format = "xml1"
-    extra_substitutions = []
-    if (defined(invoker.extra_substitutions)) {
-      extra_substitutions = invoker.extra_substitutions
-    }
-    extra_substitutions += [
+    extra_substitutions = [
       "MAC_SDK_BUILD=$mac_sdk_version",
       "MAC_SDK_NAME=$mac_sdk_name$mac_sdk_version",
       "MACOSX_DEPLOYMENT_TARGET=$mac_deployment_target",
       "CHROMIUM_MIN_SYSTEM_VERSION=$mac_min_system_version",
       "XCODE_BUILD=$xcode_build",
       "XCODE_VERSION=$xcode_version",
     ]
+    if (defined(invoker.extra_substitutions)) {
+      extra_substitutions += invoker.extra_substitutions
+    }
     plist_templates = [
       "//build/config/mac/BuildInfo.plist",
       _info_plist,

ios/chrome/test/earl_grey2/chrome_ios_eg2_test.gni

@@ -131,10 +131,7 @@ template("chrome_ios_eg2_test_app_host") {
       ios_application_icons_target,
     ]
 
-    if (!defined(extra_substitutions)) {
-      extra_substitutions = []
-    }
-    extra_substitutions += [
+    extra_substitutions = [
       "CHROMIUM_BUNDLE_ID=$bundle_identifier",
       "CHROMIUM_HANDOFF_ID=$chromium_handoff_id",
       "CHROMIUM_SHORT_NAME=$target_name",