Implementation of setSinkId() for HTMLMediaElement.

Source/modules/audio_output_devices/HTMLMediaElementAudioOutputDevice.cpp

Index: Source/modules/audio_output_devices/HTMLMediaElementAudioOutputDevice.cpp
diff --git a/Source/modules/audio_output_devices/HTMLMediaElementAudioOutputDevice.cpp b/Source/modules/audio_output_devices/HTMLMediaElementAudioOutputDevice.cpp
index 5e7fd020a86f6056034fe76be2c43acdd12b5c62..47cf9ab16abc892a2fda18485eda2891a4d17800 100644
--- a/Source/modules/audio_output_devices/HTMLMediaElementAudioOutputDevice.cpp
+++ b/Source/modules/audio_output_devices/HTMLMediaElementAudioOutputDevice.cpp
@@ -8,6 +8,7 @@
 #include "bindings/core/v8/ScriptPromiseResolver.h"
 #include "bindings/core/v8/ScriptState.h"
 #include "core/dom/ExecutionContext.h"
+#include "modules/audio_output_devices/SetSinkIdCallbacks.h"
 #include "platform/Logging.h"
 
 namespace blink {
@@ -24,10 +25,24 @@ String HTMLMediaElementAudioOutputDevice::sinkId(HTMLMediaElement& element)
     return aodElement.m_sinkId;
 }
 
-ScriptPromise HTMLMediaElementAudioOutputDevice::setSinkId(ScriptState* scriptState, HTMLMediaElement& element, const String& newSinkId)
+ScriptPromise HTMLMediaElementAudioOutputDevice::setSinkId(ScriptState* scriptState, HTMLMediaElement& element, const String& sinkId)
 {
     WTF_LOG(Media, __FUNCTION__);
-    return ScriptPromise::rejectWithDOMException(scriptState, DOMException::create(NotSupportedError, "Operation not supported"));
+    WebMediaPlayer* webMediaPlayer = element.webMediaPlayer();
+    if (!webMediaPlayer)
+        return ScriptPromise::rejectWithDOMException(scriptState, DOMException::create(AbortError, "No media player available"));
+
+    // According to spec, "id-multimedia" is equivalent to ""
+    String newSinkId = (sinkId == "id-multimedia") ? "" : sinkId;

[Mike West, 2015/06/17 11:44:37]

The spec isn't terribly clear here.
https://w3c.github.io/mediacapture-output/#idl-def-MediaDeviceId.id-multimedia
defines an enum that isn't used anywhere else in the spec. I'd suggest that
https://w3c.github.io/mediacapture-output/#widl-HTMLMediaElement-setSinkId-Pr...
should make this behavior explicit.

[Guido Urdaneta, 2015/06/17 12:25:15]

You are right. I just removed support for id-multimedia.
We can re-add it later, when the spec becomes clearer.

+    RefPtrWillBeRawPtr<ScriptPromiseResolver> resolver = ScriptPromiseResolver::create(scriptState);
+    ScriptPromise promise = resolver->promise();

[Mike West, 2015/06/17 11:44:37]

Nit: Could you just return `resolver->promise()` rather than creating the temp
variable?

[Guido Urdaneta, 2015/06/17 12:25:15]

Done.

+    HTMLMediaElementAudioOutputDevice& aodElement = HTMLMediaElementAudioOutputDevice::from(element);
+    if (newSinkId == aodElement.m_sinkId)
+        resolver->resolve();
+    else
+        webMediaPlayer->setSinkId(newSinkId, new SetSinkIdCallbacks(resolver, element, newSinkId));
+
+    return promise;
 }
 
 const char* HTMLMediaElementAudioOutputDevice::supplementName()