Add source column to chrome://policy showing the origins of policies.

tools/gritsettings/resource_ids

 # Copyright (c) 2012 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 file is used to assign starting resource ids for resources and strings
 # used by Chromium.  This is done to ensure that resource ids are unique
 # across all the grd files.  If you are adding a new grd file, please add
 # a new entry to this file.
 #
 # The first entry in the file, SRCDIR, is special: It is a relative path from
@@ skipping 241 matching lines @@
   "remoting/resources/remoting_strings.grd": {
     "messages": [29210],
   },
   "components/components_strings.grd": {
     "messages": [29660],
   },
   # Chromium strings and Google Chrome strings must start at the same id.
   # We only use one file depending on whether we're building Chromium or
   # Google Chrome.
   "components/components_chromium_strings.grd": {
-    "messages": [30140],
+    "messages": [30160],
   },
   "components/components_google_chrome_strings.grd": {
-    "messages": [30140],
+    "messages": [30160],
   },
   "components/resources/components_resources.grd": {
-    "includes": [30155],
+    "includes": [30175],
   },
   "components/resources/components_scaled_resources.grd": {
-    "structures": [30310],
+    "structures": [30350],
   },
   "third_party/WebKit/public/blink_resources.grd": {
-    "includes": [30350],
-    "structures": [30650],
+    "includes": [30370],
+    "structures": [30670],
   },
   "chrome/browser/devtools/device/webrtc/resources.grd": {
-    "includes": [30800],
+    "includes": [30820],
   },
   "chrome/browser/resources/settings/settings_resources.grd": {
-    "structures": [30900],
+    "structures": [30920],
   },
 
   # Resource ids starting at 31000 are reserved for projects built on Chromium.
 }