Add the "options_ui" extension manifest field.

extensions/extensions_strings.grd

Index: extensions/extensions_strings.grd
diff --git a/extensions/extensions_strings.grd b/extensions/extensions_strings.grd
index 603e99ffa78d227addcdb1c0a7c20737c012b4f4..f0feb8e722e0a698eb13df3b848e4e50719c93ba 100644
--- a/extensions/extensions_strings.grd
+++ b/extensions/extensions_strings.grd
@@ -190,6 +190,9 @@
       <message name="IDS_EXTENSION_LOAD_LAUNCHER_PAGE_FAILED" desc="">
         Could not load launcher page '<ph name="PAGE">$1<ex>index.html</ex></ph>'.
       </message>
+      <message name="IDS_EXTENSION_LOAD_OPTIONS_PAGE_FAILED" desc="">
+        Could not load options page '<ph name="OPTIONS_PAGE">$1<ex>page.html</ex></ph>'.
+      </message>
       <message name="IDS_EXTENSION_LOCALES_NO_DEFAULT_LOCALE_SPECIFIED" desc="">
         Localization used, but default_locale wasn't specified in the manifest.
       </message>
@@ -199,7 +202,7 @@
       <message name="IDS_EXTENSION_MANIFEST_INVALID" desc="">
         Manifest file is invalid.
       </message>
-      
+
       <!-- Host access permissions. Please keep alphabetized. -->
       <message name="IDS_EXTENSION_PROMPT_WARNING_1_HOST" desc="Permission string for access to data on one website.">
         Read and change your data on <ph name="WEBSITE_1">$1<ex>www.google.com</ex></ph>
@@ -277,7 +280,7 @@
       <message name="IDS_EXTENSION_PROMPT_WARNING_SOCKET_SPECIFIC_HOSTS" desc="Permission string for access to multiple specific computers on the local network or internet.">
         Exchange data with the computers named: <ph name="HOSTNAMES">$1<ex>foo.example.com bar.example.com</ex></ph>
       </message>
-      
+
       <!-- Device API strings. Please keep alphabetized. -->
       <message name="IDS_EXTENSION_PROMPT_WARNING_HID" desc="Permission string for access to HID devices.">
         Access your input devices