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 244 matching lines @@
   "remoting/resources/remoting_strings.grd": {
     "messages": [29560],
   },
   "components/components_strings.grd": {
     "messages": [30010],
   },
   # 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": [30270],
+    "messages": [30290],
   },
   "components/components_google_chrome_strings.grd": {
-    "messages": [30270],
+    "messages": [30290],
   },
   "components/resources/components_resources.grd": {
-    "includes": [30275],
+    "includes": [30295],
   },
   "components/resources/components_scaled_resources.grd": {
-    "structures": [30310],
+    "structures": [30330],
   },
   "third_party/WebKit/public/blink_resources.grd": {
     "includes": [30350],
-    "structures": [30650],
+    "structures": [30670],
   },
   "chrome/browser/devtools/device/webrtc/resources.grd": {
-    "includes": [30800],
+    "includes": [30820],
   },
   "chrome/browser/resources/settings/settings_resources.grd": {
-    "structures": [30900],
+    "structures": [30920],
   },
 
   # These files don't need to reserve resource ids, but are listed here so that
   # translation scripts know of their existence.
   "android_webview/java/strings/android_webview_strings.grd": {},
   "chrome/android/java/strings/android_chrome_strings.grd": {},
   "content/public/android/java/strings/android_content_strings.grd": {},
   "ui/accessibility/extensions/strings/accessibility_extensions_strings.grd": {},
   "ui/android/java/strings/android_ui_strings.grd": {},
 
   # Resource ids starting at 31000 are reserved for projects built on Chromium.
 }