Fix a DCHECK failure by registering a handler for 'dialogClose' message.

chrome/browser/ui/webui/constrained_web_dialog_ui.cc

 // Copyright (c) 2012 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 "chrome/browser/ui/webui/constrained_web_dialog_ui.h"
 
 #include <string>
 #include <vector>
 
 #include "base/bind.h"
@@ skipping 42 matching lines @@
 #if defined(ENABLE_EXTENSIONS)
   extensions::TabHelper::CreateForWebContents(web_ui->GetWebContents());
 #endif
 }
 
 ConstrainedWebDialogUI::~ConstrainedWebDialogUI() {
 }
 
 void ConstrainedWebDialogUI::RenderViewCreated(
     RenderViewHost* render_view_host) {
+  // Add a "dialogClose" callback which matches WebDialogUI behavior.
+  web_ui()->RegisterMessageCallback("dialogClose",
+      base::Bind(&ConstrainedWebDialogUI::OnDialogCloseMessage,
+                 base::Unretained(this)));
+
   ConstrainedWebDialogDelegate* delegate = GetConstrainedDelegate();
   if (!delegate)
     return;
 
   ui::WebDialogDelegate* dialog_delegate = delegate->GetWebDialogDelegate();
   std::vector<WebUIMessageHandler*> handlers;
   dialog_delegate->GetWebUIMessageHandlers(&handlers);
   render_view_host->SetWebUIProperty("dialogArguments",
                                      dialog_delegate->GetDialogArgs());
   for (std::vector<WebUIMessageHandler*>::iterator it = handlers.begin();
        it != handlers.end(); ++it) {
     web_ui()->AddMessageHandler(*it);
   }
 
-  // Add a "dialogClose" callback which matches WebDialogUI behavior.
-  web_ui()->RegisterMessageCallback("dialogClose",
-      base::Bind(&ConstrainedWebDialogUI::OnDialogCloseMessage,
-                 base::Unretained(this)));
-
   dialog_delegate->OnDialogShown(web_ui(), render_view_host);
 }
 
 void ConstrainedWebDialogUI::OnDialogCloseMessage(const base::ListValue* args) {
   ConstrainedWebDialogDelegate* delegate = GetConstrainedDelegate();
   if (!delegate)
     return;
 
   std::string json_retval;
   if (!args->empty() && !args->GetString(0, &json_retval))
@@ skipping 11 matching lines @@
 }
 
 ConstrainedWebDialogDelegate* ConstrainedWebDialogUI::GetConstrainedDelegate() {
   ConstrainedWebDialogDelegateUserData* user_data =
       static_cast<ConstrainedWebDialogDelegateUserData*>(
           web_ui()->GetWebContents()->
               GetUserData(&kConstrainedWebDialogDelegateUserDataKey));
 
   return user_data ? user_data->delegate() : NULL;
 }