gn: Generalize process_version() and move it to build/util

chrome/installer/linux/BUILD.gn

 # Copyright 2015 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.
 
 import("//build/config/chrome_build.gni")
 import("//build/config/features.gni")
 import("//build/config/sanitizers/sanitizers.gni")
+import("//build/util/process_version.gni")
 import("//build/util/version.gni")
-import("//chrome/version.gni")
 
 if (current_cpu == "x86" || current_cpu == "x64") {
   import("//media/cdm/ppapi/cdm_paths.gni")
 }
 
 assert(is_linux && is_chrome_branded)
 
 # This target builds all "normal" Linux installers.
 # GYP version: chrome/chrome_installer.gypi:linux_packages_all
 #
@@ skipping 123 matching lines @@
     ]
     outputs = [
       "$root_out_dir/installer/rpm/{{source_file_part}}",
     ]
   }
 }
 
 process_version("save_build_info") {
   # Just output the default version info variables (no template).
   process_only = true
+  sources = [
+    "//chrome/VERSION",
+    branding_file_path,
+  ]
   output = "$root_out_dir/installer/version.txt"
 }
 
 # Dependencies for all Linux installer targets.
 group("installer_deps") {
   # Though many of these things appear in data_deps further down the
   # dependency chain, they must appear here as public_deps so that they can
   # be listed as inputs to the actions that depend on ":installer_deps"
   # and are guaranteed to have been built before those actions run.
 
@@ skipping 178 matching lines @@
 # Other packages that we support that aren't included in the default "linux"
 # target.
 linux_package("trunk") {
   channel = "trunk"
 }
 if (is_asan) {
   linux_package("asan") {
     channel = "asan"
   }
 }