Implementing chrome.i18n.getMessage call, that loads message from the extensi...

chrome/common/extensions/api/extension_api.json

 [
   {
     "namespace": "extension",
     "types": [
       {
         "id": "Port",
         "type": "object",
         "description": "An object which allows two way communication with other pages.",
         "properties": {
           "name": {"type": "string"},
@@ skipping 1096 matching lines @@
         "description": "Get accept languages of browser",
         "parameters": [
           {
             "type": "function",
             "name": "callback",
             "parameters": [
               {"name": "languages", "type": "array", "items": {"type": "string"}, "description": "Array of the accept languages of the browser, such as en-US,en,zh-CN"}
             ]
           }
         ]
+      },
+      {
+        "name": "getMessage",
+        "type": "function",
+        "description": "Get a message from the extension language catalog, for a current locale.",
+        "parameters": [
+          { "type": "string",
+            "name": "message_name",
+            "description": "Message name from the extension catalog."
+          },
+          {
+            "choices": [
+              { "type": "string" },
+              {
+                "type": "array",
+                "items": { "type": "string" },
+                "minItems": 1,
+                "maxItems": 9
+              }
+            ],
+            "optional": true,
+            "description": "1 - 9 substitution parameters, if the message requires any."
+          }
+        ],
+        "returns": {
+          "type": "string",
+          "description": "Message localized for current locale."
+        }
       }
     ],
-    "events": [
-    ]
+    "events": []
   },
   {
     "namespace": "devtools",
     "types": [
     ],
     "functions": [
       {
         "name": "getTabEvents",
         "type": "function",
         "description": "EXPERIMENTAL support for timeline API",
@@ skipping 36 matching lines @@
         "type": "function",
         "description": "Logs a message during internal unit testing.",
         "parameters": [
           {"type": "string", "name": "message"}
         ]
       }
     ],
     "events": []
   }
 ]