The rest of the Presentation API IDL as stubs.

Source/modules/presentation/Presentation.h

Index: Source/modules/presentation/Presentation.h
diff --git a/Source/modules/presentation/Presentation.h b/Source/modules/presentation/Presentation.h
index be2cdae35e86df34e2d8c50bf7aa4be53934a949..97bbe859afbf52f98cdd5632f9259410049bcea8 100644
--- a/Source/modules/presentation/Presentation.h
+++ b/Source/modules/presentation/Presentation.h
@@ -5,11 +5,15 @@
 #ifndef Presentation_h
 #define Presentation_h
 
+#include "bindings/core/v8/ScriptPromise.h"
 #include "core/dom/ContextLifecycleObserver.h"
 #include "core/events/EventTarget.h"
+#include "modules/presentation/PresentationSession.h"
 
 namespace blink {
 
+class ScriptState;
+
 class Presentation final
     : public RefCountedGarbageCollectedWillBeGarbageCollectedFinalized<Presentation>
     , public EventTargetWithInlineData
@@ -27,10 +31,17 @@ public:
 
     virtual void trace(Visitor*) override;
 
+    PresentationSession* session() const;
+
+    ScriptPromise startSession(ScriptState*, const String& senderId, const String& presentationId);
+    ScriptPromise joinSession(ScriptState*, const String& senderId, const String& presentationId);
+
     DEFINE_ATTRIBUTE_EVENT_LISTENER(availablechange);
 
 private:
     explicit Presentation(ExecutionContext*);
+
+    Member<PresentationSession> m_session;
 };
 
 } // namespace blink