[DevTools] Add dialog type and return value to Page.javascriptDialog{Opening,Closed}.

Source/web/ChromeClientImpl.cpp

Index: Source/web/ChromeClientImpl.cpp
diff --git a/Source/web/ChromeClientImpl.cpp b/Source/web/ChromeClientImpl.cpp
index 4bddb6895087221ce4122e4d24d4d5edbcb7bdab..bfb4806685ed4401ed5d57bd63d07407fd239e1b 100644
--- a/Source/web/ChromeClientImpl.cpp
+++ b/Source/web/ChromeClientImpl.cpp
@@ -408,7 +408,7 @@ void ChromeClientImpl::closeWindowSoon()
 
 // Although a LocalFrame is passed in, we don't actually use it, since we
 // already know our own m_webView.
-void ChromeClientImpl::openJavaScriptAlertDelegate(LocalFrame* frame, const String& message)
+bool ChromeClientImpl::openJavaScriptAlertDelegate(LocalFrame* frame, const String& message)
 {
     notifyPopupOpeningObservers();
     WebLocalFrameImpl* webframe = WebLocalFrameImpl::fromFrame(frame);
@@ -416,7 +416,9 @@ void ChromeClientImpl::openJavaScriptAlertDelegate(LocalFrame* frame, const Stri
         if (WebUserGestureIndicator::isProcessingUserGesture())
             WebUserGestureIndicator::currentUserGestureToken().setJavascriptPrompt();
         webframe->client()->runModalAlertDialog(message);
+        return true;
     }
+    return false;
 }
 
 // See comments for openJavaScriptAlertDelegate().