Move Mime type handling to streamsPrivate API, so that it works on Desktop Chrome.

chrome/common/extensions/api/_permission_features.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.
 
 {
   "activeTab": {
     "channel": "stable",
     "extension_types": ["extension", "packaged_app"],
     "min_manifest_version": 2
   },
@@ skipping 303 matching lines @@
     "extension_types": ["packaged_app", "hosted_app", "platform_app"]
   },
   "serial": {
     "channel": "stable",
     "extension_types": ["platform_app"]
   },
   "sessionRestore": {
     "channel": "dev",
     "extension_types": ["extension", "packaged_app"]
   },
+  "streamsPrivate": {
+    "channel": "stable",
+    "extension_types": ["extension", "packaged_app", "platform_app"]

[Matt Perry, 2013/03/01 22:15:16]

I think you can move the whitelist here instead of hardcoded now. IIRC we didn't
do that before because only part of the API was whitelisted.

[Zachary Kuznia, 2013/03/04 06:09:43]

Done.

+  },
   "socket": {
     "channel": "stable",
     "extension_types": ["platform_app"]
   },
   "syncFileSystem": {
     "channel": "dev",
     "extension_types": ["platform_app"]
   },
   "systemIndicator": {
     "channel": "dev",
@@ skipping 101 matching lines @@
   },
   "webRequestBlocking": {
     "channel": "stable",
     "extension_types": ["extension", "packaged_app"]
   },
   "webview": {
     "channel": "stable",
     "extension_types": ["platform_app"]
   }
 }