Add UseCounters for BeforeInstallPromptEvent.

third_party/WebKit/Source/modules/app_banner/BeforeInstallPromptEvent.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 BeforeInstallPromptEvent_h
 #define BeforeInstallPromptEvent_h
 
 #include "bindings/core/v8/ScriptPromise.h"
 #include "bindings/core/v8/ScriptPromiseProperty.h"
 #include "modules/EventModules.h"
@@ skipping 27 matching lines @@
     static BeforeInstallPromptEvent* create(const AtomicString& name, const BeforeInstallPromptEventInit& init)
     {
         return new BeforeInstallPromptEvent(name, init);
     }
 
     Vector<String> platforms() const;
     ScriptPromise userChoice(ScriptState*);
     ScriptPromise prompt(ScriptState*);
 
     const AtomicString& interfaceName() const override;
+    void preventDefault() override;
 
     DECLARE_VIRTUAL_TRACE();
 
 private:
     BeforeInstallPromptEvent();
     BeforeInstallPromptEvent(const AtomicString& name, ExecutionContext*, const Vector<String>& platforms, int requestId, WebAppBannerClient*);
     BeforeInstallPromptEvent(const AtomicString& name, const BeforeInstallPromptEventInit&);
 
     Vector<String> m_platforms;
 
     int m_requestId;
     WebAppBannerClient* m_client;
     Member<UserChoiceProperty> m_userChoice;
     bool m_registered;
 };
 
 DEFINE_TYPE_CASTS(BeforeInstallPromptEvent, Event, event, event->interfaceName() == EventNames::BeforeInstallPromptEvent, event.interfaceName() == EventNames::BeforeInstallPromptEvent);
 
 } // namespace blink
 
 #endif // BeforeInstallPromptEvent_h