[Downloads] Open media downloads internally

chrome/browser/android/download/download_manager_service.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 "chrome/browser/android/download/download_manager_service.h"
 
 #include "base/android/jni_string.h"
 #include "base/location.h"
 #include "base/single_thread_task_runner.h"
 #include "base/threading/thread_task_runner_handle.h"
@@ skipping 423 matching lines @@
   content::DownloadManager* manager =
       content::BrowserContext::GetDownloadManager(profile);
 
   // Update notifiers to monitor any newly created DownloadManagers.
   updateNotifier(
       this, manager,
       is_off_the_record ? off_the_record_notifier_ : original_notifier_);
 
   return manager;
 }
+
+// static
+jboolean IsSupportedMimeType(
+    JNIEnv* env,
+    const JavaParamRef<jclass>& clazz,
+    const JavaParamRef<jstring>& jmime_type) {
+  std::string mime_type = ConvertJavaStringToUTF8(env, jmime_type);
+  return mime_util::IsSupportedMimeType(mime_type);
+}