Remove the ability of webpages to specify strings for the onbeforeunload dialog.

third_party/WebKit/Source/web/ChromeClientImpl.cpp

Index: third_party/WebKit/Source/web/ChromeClientImpl.cpp
diff --git a/third_party/WebKit/Source/web/ChromeClientImpl.cpp b/third_party/WebKit/Source/web/ChromeClientImpl.cpp
index 60b805e11b270bd34dc851989a09df11b70c8b0e..2cf2cbf6f2e7ce943a0754e3aec64e565055c960 100644
--- a/third_party/WebKit/Source/web/ChromeClientImpl.cpp
+++ b/third_party/WebKit/Source/web/ChromeClientImpl.cpp
@@ -399,11 +399,11 @@ bool ChromeClientImpl::canOpenBeforeUnloadConfirmPanel()
     return !!m_webView->client();
 }
 
-bool ChromeClientImpl::openBeforeUnloadConfirmPanelDelegate(LocalFrame* frame, const String& message, bool isReload)
+bool ChromeClientImpl::openBeforeUnloadConfirmPanelDelegate(LocalFrame* frame, bool isReload)
 {
     notifyPopupOpeningObservers();
     WebLocalFrameImpl* webframe = WebLocalFrameImpl::fromFrame(frame);
-    return webframe->client() && webframe->client()->runModalBeforeUnloadDialog(isReload, message);
+    return webframe->client() && webframe->client()->runModalBeforeUnloadDialog(isReload);
 }
 
 void ChromeClientImpl::closeWindowSoon()