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

extensions/shell/BUILD.gn

Index: extensions/shell/BUILD.gn
diff --git a/extensions/shell/BUILD.gn b/extensions/shell/BUILD.gn
index 2be94d510c26f933fb3bf08f24f5996e1d25de91..f14b69607de6b77a642d900c7aa2964059e5efb0 100644
--- a/extensions/shell/BUILD.gn
+++ b/extensions/shell/BUILD.gn
@@ -4,7 +4,11 @@
 
 import("//build/config/features.gni")
 import("//build/config/ui.gni")
-import("//build/util/process_version.gni")
+
+# Technically, this directory should not depend on files from src/chrome, but
+# that's where the VERSION file is. This  should probably all be moved to
+# src/build.
+import("//chrome/version.gni")
 import("//testing/test.gni")
 import("//tools/grit/grit_rule.gni")
 
@@ -276,10 +280,6 @@
 
 process_version("version_header") {
   template_file = "common/version.h.in"
-  sources = [
-    "//build/util/LASTCHANGE",
-    "//chrome/VERSION",
-  ]
   output = "$target_gen_dir/common/version.h"
 }