Add a PDF component extension

chrome/common/extensions/api/_manifest_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.
 
 // See c/c/e/features/* to understand this file, in particular feature.h,
 // simple_feature.h, and base_feature_provider.h.
 
 {
   "app": {
     "channel": "stable",
@@ skipping 225 matching lines @@
     "extension_types": ["platform_app"]
   },
   "mime_types": {
     "channel": "stable",
     "extension_types": [ "extension", "legacy_packaged_app", "platform_app" ],
     "whitelist": [
       "oickdpebdnfbgkcaoklfcdhjniefkcji",  // browser_tests
       "gbkeegbaiigmenfmjfclcdgdpimamgkj",  // QuickOffice
       "ionpfmkccalenbmnddpbmocokhaknphg",  // QuickOffice Dev
       "bpmcpldpdmajfigpchkicefoigmkfalc",  // Quickoffice component extension
-      "ehibbfinohgbchlgdbfpikodjaojhccn"   // Editor
+      "ehibbfinohgbchlgdbfpikodjaojhccn",  // Editor
+      "mhjfbmdgcfjbbpaeojofohoefgiehjai"   // PDF
     ]
   },
   "minimum_chrome_version": {
     "channel": "stable",
     "extension_types": [
       "extension", "legacy_packaged_app", "hosted_app", "platform_app"
     ]
   },
   "nacl_modules": {
     "channel": "stable",
@@ skipping 144 matching lines @@
     "extension_types": [
       "extension", "legacy_packaged_app", "hosted_app"
     ]
   },
   "webview": {
     "channel": "dev",
     "extension_types": ["platform_app"],
     "min_manifest_version": 2
   }
 }