Make channel available in Java via ChromeVersionConstants.java.

chrome/version.gni

 # Copyright 2014 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.
 
 # Runs the version processing script over the given template file to produce
 # an output file. This is used for generating various forms of files that
 # incorporate the product name and version.
 #
 # This template automatically includes VERSION, LASTCHANGE, and BRANDING,
 #
 # Parameters:
 #   source:
 #     File name of source template file to read.
 #
 #   output:
 #     File name of file to write.
 #
+#   extra_args:
+#     Extra arguments to pass to version.py.
+#
 #   visibility (optional)
 #
 # Example:
 #   process_version("myversion") {
 #     source = "myfile.h.in"
 #     output = "$target_gen_dir/myfile.h"
+#     extra_args = ["-e", "FOO=42"]
 #   }
 template("process_version") {
   assert(defined(invoker.source), "Source must be defined for $target_name")
   assert(defined(invoker.output), "Output must be defined for $target_name")
 
   action(target_name) {
     if (defined(invoker.visibility)) {
       visibility = invoker.visibility
     }
     script = "//build/util/version.py"
@@ skipping 12 matching lines @@
       lastchange_path,
       branding_path,
     ]
 
     outputs = [ invoker.output ]
 
     args = [
       "-f", rebase_path(version_path, root_build_dir),
       "-f", rebase_path(branding_path, root_build_dir),
       "-f", rebase_path(lastchange_path, root_build_dir),
-      rebase_path(invoker.source, root_build_dir),
-      rebase_path(invoker.output, root_build_dir),
+      "-i", rebase_path(invoker.source, root_build_dir),
+      "-o", rebase_path(invoker.output, root_build_dir),
     ]
+
+    if (defined(invoker.extra_args)) {
+      args += invoker.extra_args
+    }
   }
 }