Add a tray notification UI for speech input recording in the extension API.

chrome/common/extensions/api/extension_api.json

 [
   {
     "namespace": "extension",
     "unprivileged": true,
     "types": [
       {
         "id": "MessageSender",
         "type": "object",
         "description": "An object containing information about the script context that sent a message or request.",
         "properties": {
@@ skipping 510 matching lines @@
         "type": "object",
         "description": "Object describing the options used for speech recognition.",
         "properties": {
           "language": {
             "type": "string",
             "optional": true,
             "description": "BCP-47 language code of the language to recognize. When set to 'auto' or not defined defaults to user's most preferred content language. Will use 'en-US' if not supported or invalid."
           },
           "grammar": {
             "type": "string",
-            "description": "Name of the grammar to use. Defaults to 'builtin:search'.",
+            "description": "Name of the grammar to use. Defaults to 'builtin:dictation'.",
             "optional": true
           },
           "filterProfanities": {
             "type": "boolean",
             "optional": true,
             "description": "Enable or disable profanity filtering. Will use the default Chrome filtering settings if not set."
           }
         }
       },
       {
@@ skipping 8667 matching lines @@
                   }
                 }
               }
             ]
           }
         ]
       }
     ]
   }
 ]