[Mac/GN] Get chrome and chrome_framework building.

build/util/branding.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 exposes the Chrome branding as GN variables for use in build files.
+#
+# PREFER NOT TO USE THESE. The GYP build uses this kind of thing extensively.

[Robert Sesek, 2016/04/29 16:45:53]

I know this is not ideal, but the bundle packaging needs these values at
build-time to choose output names.

An alternative would be to have a .gni file that declares
chrome_product_full_name as a string instead.

Depending on your opinion, I will either add the values here (mac_bundle_id and
mac_creator)
https://code.google.com/p/chromium/codesearch#chromium/src/build/chrome_setti...
into BRANDING or into the aforementioned gni file.

+# However, it is far better to write an action to generate a file at
+# build-time with the information you need. This allows better dependency
+# checking and GN will run faster.
+#
+# These values should only be used if you REALLY need to depend on them at
+# build-time, for example, in the computation of output file names.
+
+import("//build/config/chrome_build.gni")
+
+_branding_file = "//chrome/app/theme/$branding_path_component/BRANDING"
+_result = exec_script("version.py",
+                      [
+                        "-f",
+                        rebase_path(_branding_file, root_build_dir),
+                        "-t",
+                        "@PRODUCT_FULLNAME@",
+                      ],
+                      "trim string",
+                      [ _branding_file ])
+
+chrome_product_full_name = _result