Presentation API: add UMA.

Source/modules/presentation/PresentationRequest.h

 // 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 PresentationRequest_h
 #define PresentationRequest_h
 
 #include "bindings/core/v8/ScriptPromise.h"
 #include "core/dom/ActiveDOMObject.h"
 #include "core/events/EventTarget.h"
@@ skipping 12 matching lines @@
     WILL_BE_USING_GARBAGE_COLLECTED_MIXIN(PresentationRequest);
     DEFINE_WRAPPERTYPEINFO();
 public:
     ~PresentationRequest() = default;
 
     static PresentationRequest* create(ExecutionContext*, const String& url, ExceptionState&);
 
     // EventTarget implementation.
     const AtomicString& interfaceName() const override;
     ExecutionContext* executionContext() const override;
+    bool addEventListener(const AtomicString& eventType, PassRefPtrWillBeRawPtr<EventListener>, bool capture) override;
 
     // ActiveDOMObject implementation.
     bool hasPendingActivity() const;
 
     ScriptPromise start(ScriptState*);
     ScriptPromise join(ScriptState*, const String& id);
     ScriptPromise getAvailability(ScriptState*);
 
     const KURL& url() const;
 
     DEFINE_ATTRIBUTE_EVENT_LISTENER(sessionconnect);
 
     DECLARE_VIRTUAL_TRACE();
 
 private:
     PresentationRequest(ExecutionContext*, const KURL&);
 
     KURL m_url;
 };
 
 } // namespace blink
 
 #endif // PresentationRequest_h