Encrypted Media: Add DefaultCdmFactory.

media/cdm/default_cdm_factory.cc

+// Copyright 2014 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 "media/cdm/default_cdm_factory.h"
+
+#include "media/base/key_systems.h"
+#include "media/cdm/aes_decryptor.h"
+
+namespace media {
+
+DefaultCdmFactory::DefaultCdmFactory() {
+}
+
+DefaultCdmFactory::~DefaultCdmFactory() {
+}
+
+scoped_ptr<MediaKeys> DefaultCdmFactory::Create(
+    const std::string& key_system,
+    const GURL& security_origin,
+    const SessionMessageCB& session_message_cb,
+    const SessionClosedCB& session_closed_cb,
+    const SessionErrorCB& session_error_cb,
+    const SessionKeysChangeCB& session_keys_change_cb,
+    const SessionExpirationUpdateCB& session_expiration_update_cb) {
+  if (CanUseAesDecryptor(key_system)) {
+    return make_scoped_ptr(new AesDecryptor(
+        session_message_cb, session_closed_cb, session_keys_change_cb));
+  }
+
+  return nullptr;
+}
+
+}  // namespace media