[Mac/GN] Port tweak_info_plist.py and run it on //content targets.

build/config/mac/base_rules.gni

 # Copyright 2016 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.
 
 # This file contains rules that are shared between Mac and iOS.
 
 import("//build/toolchain/toolchain.gni")
 
 if (is_mac) {
   import("//build/config/mac/mac_sdk.gni")
@@ skipping 46 matching lines @@
           "-s=BUILD_MACHINE_OS_BUILD=$machine_os_build",
           "-s=EXECUTABLE_NAME=$executable_name",
           "-s=GCC_VERSION=com.apple.compilers.llvm.clang.1_0",
           "-s=PRODUCT_NAME=$executable_name",
           "-s=XCODE_BUILD=$xcode_build",
           "-s=XCODE_VERSION=$xcode_version",
           "-o=" + rebase_path(outputs[0], root_build_dir),
           "-f=" + invoker.format,
         ] + rebase_path(sources, root_build_dir)
     args = [ "@{{response_file_name}}" ]
+    forward_variables_from(invoker,
+                           [
+                             "testonly",
+                             "deps",
+                           ])
   }
 }
 
 # This is used as the base template for both iOS and Mac frameworks.
 #
 # By default, the bundle target this template generates does not link the
 # resulting framework into anything that depends on it. If a dependency wants
 # a link-time (as well as build-time) dependency on the framework bundle,
 # depend against "$target_name+link". If only the build-time dependency is
 # required (e.g., for copying into another bundle), then use "$target_name".
@@ skipping 235 matching lines @@
       "$target_gen_dir/{{source_name_part}}.nib",
     ]
     args = [
              "--input",
              "{{source}}",
              "--output",
              rebase_path("$target_gen_dir/{{source_name_part}}.nib"),
            ] + ibtool_flags
   }
 }