Update references to the extension messaging APIs to point to the "runtime"

chrome/common/extensions/api/input_ime.json

 // 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.
 
 [
   {
     "namespace": "input.ime",
     "platforms": ["chromeos"],
     "types": [
       {
@@ skipping 73 matching lines @@
                     }
                   }
                 }
               }
             }
           },
           {
             "type": "function",
             "name": "callback",
             "optional": true,
-            "description": "Called when the operation completes with a boolean indicating if the text was accepted or not. On failure, chrome.extension.lastError is set.",
+            "description": "Called when the operation completes with a boolean indicating if the text was accepted or not. On failure, chrome.runtime.lastError is set.",
             "parameters": [
               {
                 "name": "success",
                 "type": "boolean"
               }
             ]
           }
         ]
       },
       {
         "name": "clearComposition",
         "type": "function",
         "description": "Clear the current composition. If this extension does not own the active IME, this fails.",
         "parameters": [
           {
             "name": "parameters",
             "type": "object",
             "properties": {
               "contextID": {
                 "description": "ID of the context where the composition will be cleared",
                 "type": "integer"
               }
             }
           },
           {
             "type": "function",
             "name": "callback",
             "optional": true,
-            "description": "Called when the operation completes with a boolean indicating if the text was accepted or not. On failure, chrome.extension.lastError is set.",
+            "description": "Called when the operation completes with a boolean indicating if the text was accepted or not. On failure, chrome.runtime.lastError is set.",
             "parameters": [
               {
                 "name": "success",
                 "type": "boolean"
               }
             ]
           }
         ]
       },
       {
@@ skipping 12 matching lines @@
               "text": {
                 "description": "The text to commit",
                 "type": "string"
               }
             }
           },
           {
             "type": "function",
             "name": "callback",
             "optional": true,
-            "description": "Called when the operation completes with a boolean indicating if the text was accepted or not. On failure, chrome.extension.lastError is set.",
+            "description": "Called when the operation completes with a boolean indicating if the text was accepted or not. On failure, chrome.runtime.lastError is set.",
             "parameters": [
               {
                 "name": "success",
                 "type": "boolean"
               }
             ]
           }
         ]
       },
       {
@@ skipping 382 matching lines @@
           {
             "type": "string",
             "name": "name",
             "description": "Name of the MenuItem which was activated"
           }
         ]
       }
     ]
   }
 ]