Removes the extension_types property for the imageWritePrivate API.

chrome/common/extensions/api/_api_features.json

 // Copyright 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.
 
 // This features file defines extension APIs implemented under src/chrome.
 // See chrome/common/extensions/api/_features.md to understand this file, as
 // well as feature.h, simple_feature.h, and base_feature_provider.h.
 //
 // Note that specifying "web_page", "blessed_web_page", or "all" as a context
 // type will require manually updating chrome/renderer/resources/dispatcher.cc.
@@ skipping 658 matching lines @@
   "processes": {
     "dependencies": ["permission:processes"],
     "contexts": ["blessed_extension"]
   },
   "proxy": {
     "dependencies": ["permission:proxy"],
     "contexts": ["blessed_extension"]
   },
   "imageWriterPrivate": {
     "dependencies": ["permission:imageWriterPrivate"],
-    "extension_types": ["extension", "platform_app"],
     "contexts": ["blessed_extension"]
   },
   "quickUnlockPrivate": {
     "channel": "stable",
     "contexts": ["webui"],
     "matches": [
       "chrome://md-settings/*",
       "chrome://settings/*",
       "chrome://settings-frame/*"
     ],
@@ skipping 141 matching lines @@
     "internal": true,
     "channel": "stable",
     "dependencies": ["permission:webview"],
     "contexts": ["blessed_extension"]
   },
   "windows": {
     "dependencies": ["api:tabs"],
     "contexts": ["blessed_extension"]
   }
 }