Add a launchApp method to extension management 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 3921 matching lines @@
         "type": "object",
         "properties": {
           "id": {
             "description": "The extension's unique identifier.",
             "type": "string"
           },
           "name": {
             "description": "The name of this extension or app.",
             "type": "string"
           },
+          "version": {
+            "description": "The <a href='manifest.html#version'>version</a> of this extension or app.",
+            "type": "string"
+          },
           "enabled": {
             "description": "Whether it is currently enabled or disabled.",
             "type": "boolean"
           },
           "enabled": {
             "description": "Whether it is currently enabled or disabled.",
             "type": "boolean"
           },
           "isApp": {
             "description": "True if this is an app.",
@@ skipping 72 matching lines @@
             "type": "string",
             "description": "This should be the id from an item of $ref:ExtensionInfo."
           },
           {
             "name": "callback",
             "type": "function",
             "optional": "true",
             "parameters": []
           }
         ]
+      },
+      {
+        "name": "launchApp",
+        "description": "Launches an application.",
+        "parameters": [
+          {
+            "name": "id",
+            "type": "string",
+            "description": "The extension id of the application."
+          },
+          {
+            "name": "callback",
+            "type": "function",
+            "optional": "true",
+            "parameters": []
+          }          
+        ]
       }
     ],
     "events": [
       {
         "name": "onInstalled",
         "description": "Fired when an app or extension has been installed.",
         "type": "function",
         "parameters": [{"name": "info", "$ref":"ExtensionInfo"}]
       },
       {
@@ skipping 70 matching lines @@
         "name": "setStoreLogin",
         "description": "Set a preference value with the store login.",
         "parameters": [
           { "name": "login", "type": "string" },
           { "name": "callback", "type": "function", "optional": "true" }
         ]
       }
     ]
   }
 ]