The rest of the Presentation API IDL as stubs.

Source/modules/presentation/Presentation.cpp

 // 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 "config.h"
 #include "modules/presentation/Presentation.h"
 
+#include "bindings/core/v8/ScriptPromise.h"
+#include "bindings/core/v8/ScriptPromiseResolver.h"
+#include "bindings/core/v8/ScriptState.h"
+#include "core/dom/DOMException.h"
 #include "modules/EventTargetModules.h"
 
 namespace blink {
 
 Presentation::Presentation(ExecutionContext* executionContext)
     : ContextLifecycleObserver(executionContext)
 {
 }
 
 Presentation::~Presentation()
@@ skipping 12 matching lines @@
 }
 
 ExecutionContext* Presentation::executionContext() const
 {
     return ContextLifecycleObserver::executionContext();
 }
 
 void Presentation::trace(Visitor* visitor)
 {
     EventTargetWithInlineData::trace(visitor);
+    visitor->trace(m_session);

[sof, 2014/10/31 13:28:47]

nit: the convention is to trace the local members first, then delegate. can be
tidied in a followup.

+}
+
+PresentationSession* Presentation::session() const
+{
+    return m_session.get();
+}
+
+ScriptPromise Presentation::startSession(ScriptState* state, const String& senderId, const String& presentationId)
+{
+    RefPtr<ScriptPromiseResolver> resolver = ScriptPromiseResolver::create(state);
+    ScriptPromise promise = resolver->promise();
+    resolver->reject(DOMException::create(NotSupportedError, "The method is not supported yet."));
+    return promise;
+}
+
+ScriptPromise Presentation::joinSession(ScriptState* state, const String& senderId, const String& presentationId)
+{
+    RefPtr<ScriptPromiseResolver> resolver = ScriptPromiseResolver::create(state);
+    ScriptPromise promise = resolver->promise();
+    resolver->reject(DOMException::create(NotSupportedError, "The method is not supported yet."));
+    return promise;
 }
 
 } // namespace blink