[Mac/GN] Initial mac_app_bundle template.

content/shell/BUILD.gn

Index: content/shell/BUILD.gn
diff --git a/content/shell/BUILD.gn b/content/shell/BUILD.gn
index e12ee811abc3f7d38ffc1effb0590656169db492..5437060f55d5c25cac00084de818c857c5c5b309 100644
--- a/content/shell/BUILD.gn
+++ b/content/shell/BUILD.gn
@@ -13,6 +13,8 @@ import("//tools/grit/repack.gni")
 import("//tools/grit/grit_rule.gni")
 if (is_android) {
   import("//build/config/android/config.gni")
+} else if (is_mac) {
+  import("//build/config/mac/rules.gni")
 }
 
 declare_args() {
@@ -520,6 +522,18 @@ if (is_mac) {
       ":content_shell_lib",
     ]
   }
+
+  mac_app_bundle("content_shell_helper_app") {
+    testonly = true
+    output_name = "$content_shell_product_name Helper"
+    sources = [
+      "app/shell_main.cc",
+    ]
+    deps = [
+      ":framework",
+    ]
+    info_plist = "app/helper-Info.plist"
+  }
 }
 
 mojom("mojo_bindings") {