Add hooks for BeforeInstallPromptEvent to be redispatched.

Source/modules/app_banner/BeforeInstallPromptEvent.cpp

 // 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.
 
 #include "config.h"
 #include "modules/app_banner/BeforeInstallPromptEvent.h"
 
 #include "bindings/core/v8/CallbackPromiseAdapter.h"
 #include "bindings/core/v8/ScriptPromiseResolver.h"
 #include "modules/app_banner/AppBannerPromptResult.h"
 #include "modules/app_banner/BeforeInstallPromptEventInit.h"
 #include "public/platform/modules/app_banner/WebAppBannerClient.h"
 
 namespace blink {
 
 BeforeInstallPromptEvent::BeforeInstallPromptEvent()
 {
 }
 
 BeforeInstallPromptEvent::BeforeInstallPromptEvent(const AtomicString& name, const Vector<String>& platforms, int requestId, WebAppBannerClient* client)
     : Event(name, false, true)
     , m_platforms(platforms)
     , m_requestId(requestId)
     , m_client(client)
+    , m_redispatched(false)
 {
 }
 
 BeforeInstallPromptEvent::BeforeInstallPromptEvent(const AtomicString& name, const BeforeInstallPromptEventInit& init)
     : Event(name, false, true)
     , m_platforms(init.platforms())
     , m_requestId(-1)
     , m_client(nullptr)
+    , m_redispatched(false)
 {
 }
 
 BeforeInstallPromptEvent::~BeforeInstallPromptEvent()
 {
 }
 
 Vector<String> BeforeInstallPromptEvent::platforms() const
 {
     return m_platforms;
 }
 
 ScriptPromise BeforeInstallPromptEvent::userChoice(ScriptState* scriptState)
 {
     if (m_userChoice.isEmpty() && m_client) {
         ASSERT(m_requestId != -1);
         RefPtrWillBeRawPtr<ScriptPromiseResolver> resolver = ScriptPromiseResolver::create(scriptState);
         m_userChoice = resolver->promise();
         m_client->registerBannerCallbacks(m_requestId, new CallbackPromiseAdapter<AppBannerPromptResult, void>(resolver));
     }
 
     return m_userChoice;
 }
 
 const AtomicString& BeforeInstallPromptEvent::interfaceName() const
 {
     return EventNames::BeforeInstallPromptEvent;
 }
 
+ScriptPromise BeforeInstallPromptEvent::prompt(ScriptState* scriptState)
+{
+    RefPtrWillBeRawPtr<ScriptPromiseResolver> resolver = ScriptPromiseResolver::create(scriptState);
+    ScriptPromise promise = resolver->promise();

[mlamouri (slow - plz ping), 2015/06/11 00:42:17]

You probably don't need a |resolver| or a |promise| here. You could simply call
ScriptPromise::cast() and ScriptPromise::reject().

+    if (m_client && defaultPrevented() && !m_redispatched) {
+        ASSERT(m_requestId != -1);
+        m_redispatched = true;
+        m_client->resolveEventRedispatch(m_requestId);
+        resolver->resolve();
+        userChoice(scriptState);

[mlamouri (slow - plz ping), 2015/06/11 00:42:17]

Why do you call that?

+    } else {
+        resolver->reject();

[mlamouri (slow - plz ping), 2015/06/11 00:42:17]

I think you should reject with an InvalidState error.

+    }
+    return promise;
+}
+
 } // namespace blink