Add option to GRIT to provide a resource ordering input file.

tools/grit/grit_rule.gni

Index: tools/grit/grit_rule.gni
diff --git a/tools/grit/grit_rule.gni b/tools/grit/grit_rule.gni
index 00dd9258ec2077984a0c104fb4cd7d52246a6bb3..eab19564c1f2da85397b17c93305660e768585c0 100644
--- a/tools/grit/grit_rule.gni
+++ b/tools/grit/grit_rule.gni
@@ -249,6 +249,11 @@ _js_minifier = "//third_party/closure_compiler/js_minify.py"
 grit_resource_id_file = "//tools/gritsettings/resource_ids"
 grit_info_script = "//tools/grit/grit_info.py"
 
+grit_predetermined_resource_ids_file = ""
+
+# TODO(asvitkine): Add platform-specific resource id file paths here.
+#                  http://crbug.com/692670
+
 template("grit") {
   assert(defined(invoker.source),
          "\"source\" must be defined for the grit template $target_name")
@@ -301,6 +306,12 @@ template("grit") {
       rebase_path(resource_ids, root_build_dir),
     ]
   }
+  if (grit_predetermined_resource_ids_file != "") {
+    grit_flags += [
+      "-p",
+      rebase_path(grit_predetermined_resource_ids_file, root_build_dir),
+    ]
+  }
 
   if (defined(invoker.source_is_generated)) {
     source_is_generated = invoker.source_is_generated