Add a check to the registry before the intent infobar is shown.

chrome/browser/intents/register_intent_handler_infobar_delegate.h

 // Copyright (c) 2011 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.
 
 #ifndef CHROME_BROWSER_INTENTS_REGISTER_INTENT_HANDLER_INFOBAR_DELEGATE_H_
 #define CHROME_BROWSER_INTENTS_REGISTER_INTENT_HANDLER_INFOBAR_DELEGATE_H_
 #pragma once
 
 #include "base/basictypes.h"
 #include "base/string16.h"
 #include "chrome/browser/tab_contents/confirm_infobar_delegate.h"
 #include "webkit/glue/web_intent_service_data.h"
 
+class InfoBarTabHelper;
 class TabContents;
 class WebIntentsRegistry;
 
 // The InfoBar used to request permission for a site to be registered as an
 // Intent handler.
 class RegisterIntentHandlerInfoBarDelegate : public ConfirmInfoBarDelegate {
  public:
   RegisterIntentHandlerInfoBarDelegate(
       InfoBarTabHelper* infobar_helper,
       WebIntentsRegistry* registry,
       const webkit_glue::WebIntentServiceData& service);
 
   // ConfirmInfoBarDelegate implementation.
   virtual Type GetInfoBarType() const OVERRIDE;
   virtual string16 GetMessageText() const OVERRIDE;
   virtual string16 GetButtonLabel(InfoBarButton button) const OVERRIDE;
   virtual bool Accept() OVERRIDE;
   virtual string16 GetLinkText() const OVERRIDE;
   virtual bool LinkClicked(WindowOpenDisposition disposition) OVERRIDE;
 
+  // Shows the intent registration infobar if |service| has not already been
+  // registered. Else no-op.

[James Hawkins, 2011/11/09 17:32:42]

Grammar police: Sentence fragment; it's clear the former only happens if the
condition is met, so I'd say it's OK to remove this part of the comment.

[Greg Billock, 2011/11/10 00:21:31]

Done.

+  // |infobar_helper| is the infobar controller for the tab in which the infobar
+  // may be shown. Must not be null.

[James Hawkins, 2011/11/09 17:32:42]

nit: s/null/NULL/ here and elsewhere.

[Greg Billock, 2011/11/10 00:21:31]

Done.

+  // |registry| is the data source for web intents. Must not be null.
+  // |service| is the candidate service to show the infobar for.
+  static void MaybeShowIntentInfoBar(
+      InfoBarTabHelper* infobar_helper,
+      WebIntentsRegistry* registry,
+      const webkit_glue::WebIntentServiceData& service);
+
  private:
   // The web intents registry to use. Weak pointer.
   WebIntentsRegistry* registry_;
 
   // The cached intent service data bundle passed up from the renderer.
   webkit_glue::WebIntentServiceData service_;
 
   DISALLOW_COPY_AND_ASSIGN(RegisterIntentHandlerInfoBarDelegate);
 };
 
 #endif  // CHROME_BROWSER_INTENTS_REGISTER_INTENT_HANDLER_INFOBAR_DELEGATE_H_