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

Source/core/page/ChromeClient.h

Index: Source/core/page/ChromeClient.h
diff --git a/Source/core/page/ChromeClient.h b/Source/core/page/ChromeClient.h
index 85d7605910c7d8d9a7a483ea5759a63b15ef0a0e..b6a62adcecae4cb7bfd73b3e786ed33d1252e38a 100644
--- a/Source/core/page/ChromeClient.h
+++ b/Source/core/page/ChromeClient.h
@@ -127,7 +127,7 @@ public:
 
     virtual void closeWindowSoon() = 0;
 
-    void openJavaScriptAlert(LocalFrame*, const String&);
+    bool openJavaScriptAlert(LocalFrame*, const String&);
     bool openJavaScriptConfirm(LocalFrame*, const String&);
     bool openJavaScriptPrompt(LocalFrame*, const String& message, const String& defaultValue, String& result);
     virtual void setStatusbarText(const String&) = 0;
@@ -250,7 +250,7 @@ protected:
     virtual void showMouseOverURL(const HitTestResult&) = 0;
     virtual void setWindowRect(const IntRect&) = 0;
     virtual bool openBeforeUnloadConfirmPanelDelegate(LocalFrame*, const String& message) = 0;
-    virtual void openJavaScriptAlertDelegate(LocalFrame*, const String&) = 0;
+    virtual bool openJavaScriptAlertDelegate(LocalFrame*, const String&) = 0;
     virtual bool openJavaScriptConfirmDelegate(LocalFrame*, const String&) = 0;
     virtual bool openJavaScriptPromptDelegate(LocalFrame*, const String& message, const String& defaultValue, String& result) = 0;
     virtual void printDelegate(LocalFrame*) = 0;