Implement setSinkId() for media elements without src.

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

Index: third_party/WebKit/Source/modules/audio_output_devices/AudioOutputDeviceClient.h
diff --git a/third_party/WebKit/Source/modules/audio_output_devices/AudioOutputDeviceClient.h b/third_party/WebKit/Source/modules/audio_output_devices/AudioOutputDeviceClient.h
new file mode 100644
index 0000000000000000000000000000000000000000..9b2e39e7e3279266542fd93758f91e1b5f18d90d
--- /dev/null
+++ b/third_party/WebKit/Source/modules/audio_output_devices/AudioOutputDeviceClient.h
@@ -0,0 +1,38 @@
+// 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.
+
+#ifndef AudioOutputDeviceClient_h
+#define AudioOutputDeviceClient_h
+
+#include "bindings/core/v8/ScriptPromise.h"
+#include "modules/ModulesExport.h"
+#include "platform/Supplementable.h"
+#include "public/platform/WebSetSinkIdCallbacks.h"
+#include "wtf/PassOwnPtr.h"
+
+namespace blink {
+
+class ExecutionContext;
+class LocalFrame;
+class WebString;
+class ScriptState;
+
+class AudioOutputDeviceClient : public WillBeHeapSupplement<LocalFrame> {

[jochen (gone - plz use gerrit), 2015/10/28 14:18:49]

why do you need this interface? all usages of the impl class appear to be
internal to blink?

[Guido Urdaneta, 2015/10/28 15:58:44]

I see the following choices:

a) Implement in web/: 
Not possible because 
modules/audio_output_devices/HTMLMediaElementAudioOutputDevices.cpp needs access
to checkIfAudioSinkExistsAndIsAuthorized() and it is forbidden to include  web/
from modules/.

b) Implement in modules/audio_output_devices/:
Not possible because the implementation of
checkIfAudioSinkExistsAndIsAuthorized() needs to include web/ and public/web to
access WebLocalFrameImpl and WebFrameClient, and it is forbidden to include web/
and public/web/ from modules/.

c) Put the .h in modules/ and the .cpp in web/, but I don't think that is
allowed either.

Is there another way?

[jochen (gone - plz use gerrit), 2015/10/28 16:06:47]

that looks a bit like hiding a layering violation to me... adding haraken for
his input

[haraken, 2015/10/28 16:15:40]

This is a common pattern to bypass a disallowed dependency from modules/ to
web/. So looks good.

+public:
+    virtual ~AudioOutputDeviceClient() {}
+
+    // Checks that a given sink exists and has permissions to be used from the
+    // origin of the current frame.
+    virtual void checkAudioSink(ExecutionContext*, const WebString& sinkId, PassOwnPtr<WebSetSinkIdCallbacks>) = 0;
+
+    // WillBeHeapSupplement requirements.
+    static AudioOutputDeviceClient* from(ExecutionContext*);
+    static const char* supplementName();
+};
+
+MODULES_EXPORT void provideAudioOutputDeviceClientTo(LocalFrame&, PassOwnPtrWillBeRawPtr<AudioOutputDeviceClient>);
+
+} // namespace blink
+
+#endif // AudioOutputDeviceClient_h