Adds IME switching private APIs.

chrome/common/extensions/api/input_method_private.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": "inputMethodPrivate",
     "platforms": ["chromeos"],
     "description": "none",
     "functions": [
       {
-        "name": "get",
+        "name": "getInputMethods",
+        "type": "function",
+        "description": "Gets all whitelisted input methods.",
+        "parameters": [
+          {
+            "name": "callback",
+            "type": "function",
+            "optional": false,
+            "description": "Callback which is called with the input method objects.",
+            "parameters": [
+              {
+                "name": "inputMethods",
+                "type": "array",
+                "description": "Whitelisted input method objects.",
+                "items": {
+                  "type": "object",
+                  "properties": {
+                    "id": {"type": "string"},
+                    "name": {"type": "string"},
+                    "indicator": {"type": "string"}
+                  }
+                }
+              }
+            ]
+          }
+        ]
+      }, {
+        "name": "getCurrentInputMethod",
         "type": "function",
         "description": "Gets the current input method.",
         "parameters": [
           {
             "name": "callback",
             "type": "function",
             "optional": false,
             "description": "Callback which is called with the current input method.",
             "parameters": [
               {
                 "name": "inputMethodId",
                 "type": "string",
                 "description": "Current input method."
               }
             ]
           }
         ]
       }, {
+        "name": "setCurrentInputMethod",
+        "type": "function",
+        "description": "Sets the current input method.",
+        "parameters": [
+          {
+            "name": "inputMethodId",
+            "type": "string",
+            "optional": false,
+            "description": "The input method ID to be set as current input method."
+          },
+          {
+            "name": "callback",
+            "type": "function",
+            "optional": true,
+            "description": "Callback which is called once the current input method is set or error occurs.",
+            "parameters": [
+              {
+                "name": "success",
+                "type": "boolean",

[not at google - send to devlin, 2014/06/06 16:36:04]

more idiomatic would be a void return value, but set an error on failure (which
would end up on chrome.runtime.lastError).

[Shu Chen, 2014/06/07 05:31:09]

Done.

+                "description": "Whether the current input method is successfully set."
+              }
+            ]
+          }
+        ]
+      }, {
         "name": "startIme",
         "type": "function",
         "description": "Notify to input method engine to be ready to accept events.",
         "parameters" : []
       }
     ],
     "events": [
       {
         "name": "onChanged",
         "type": "function",
         "description": "Fired when the input method is changed.",
         "parameters": [
           {
             "name": "newInputMethodId",
             "type": "string",
             "description": "New input method which is being used."
           }
         ]
       }
     ]
   }
 ]