Assign "application/vnd.android.package-archive" type to APK files on ChromeOS.

net/base/mime_extension_chromeos.cc

 // Copyright 2015 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.
 
 #include "net/base/mime_extension_chromeos.h"
 
 #include "base/logging.h"
 #include "net/base/mime_util.h"
 
 namespace net {
 namespace chromeos {
 
 namespace {
 
 static const net::MimeInfo mimetype_extension_mapping[] = {
     {"application/epub+zip", "epub"},
+    {"application/vnd.android.package-archive", "apk"},
     {"application/zip", "zip"},
     {"text/calendar", "ics"},
 };
 }  // namespace
 
 // On linux, chrome uses xdgmime to read extension-mimetype database (e.g.
 // /usr/share/mime) and estimate mime type from extension. However ChromeOS does
 // not have such database in it, we use |mimetype_extension_mapping| to resolve
 // mime type on ChromeOS.
 bool GetPlatformMimeTypeFromExtension(const base::FilePath::StringType& ext,
                                       std::string* mime_type) {
   base::FilePath path_ext(ext);
   const std::string ext_narrow_str = path_ext.AsUTF8Unsafe();
   const char* result =
       net::FindMimeType(mimetype_extension_mapping,
                         arraysize(mimetype_extension_mapping), ext_narrow_str);
   if (result) {
     *mime_type = result;
     return true;
   }
 
   return false;
 }
 }  // namespace chromeos
 }  // namespace net