Implement setSinkId() for media elements without src.

third_party/WebKit/Source/modules/audio_output_devices/AudioOutputDeviceClient.cpp

+// 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 "config.h"
+#include "modules/audio_output_devices/AudioOutputDeviceClient.h"
+
+#include "core/dom/Document.h"
+#include "core/dom/ExecutionContext.h"
+#include "core/frame/LocalFrame.h"
+
+namespace blink {
+
+const char* AudioOutputDeviceClient::supplementName()
+{
+    return "AudioOutputDeviceClient";
+}
+
+AudioOutputDeviceClient* AudioOutputDeviceClient::from(ExecutionContext* context)
+{
+    if (!context->isDocument())
+        return nullptr;
+
+    const Document* document = toDocument(context);
+    if (!document->frame() || !document->frame()->isLocalFrame())
+        return nullptr;
+
+    return static_cast<AudioOutputDeviceClient*>(WillBeHeapSupplement<LocalFrame>::from(document->frame(), supplementName()));
+}
+
+void provideAudioOutputDeviceClientTo(LocalFrame& frame, PassOwnPtrWillBeRawPtr<AudioOutputDeviceClient> client)
+{
+    frame.provideSupplement(AudioOutputDeviceClient::supplementName(), client);
+}
+
+} // namespace blink