Refactor media stream infobar delegate code and also fix a typo

chrome/browser/infobars/infobar_delegate.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/infobars/infobar_delegate.h"
 
 #include "base/logging.h"
 #include "build/build_config.h"
 #include "chrome/browser/infobars/infobar_tab_helper.h"
 #include "content/public/browser/navigation_controller.h"
@@ skipping 50 matching lines @@
 
 InsecureContentInfoBarDelegate*
     InfoBarDelegate::AsInsecureContentInfoBarDelegate() {
   return NULL;
 }
 
 LinkInfoBarDelegate* InfoBarDelegate::AsLinkInfoBarDelegate() {
   return NULL;
 }
 
-MediaStreamInfoBarDelegate* InfoBarDelegate::AsMediaStreamInfobarDelegate() {
+MediaStreamInfoBarDelegate* InfoBarDelegate::AsMediaStreamInfoBarDelegate() {
   return NULL;
 }
 
 RegisterProtocolHandlerInfoBarDelegate*
     InfoBarDelegate::AsRegisterProtocolHandlerInfoBarDelegate() {
   return NULL;
 }
 
 ThemeInstalledInfoBarDelegate*
     InfoBarDelegate::AsThemePreviewInfobarDelegate() {
@@ skipping 23 matching lines @@
   return (contents_unique_id_ != details.entry->GetUniqueID()) ||
       (content::PageTransitionStripQualifier(
           details.entry->GetTransitionType()) ==
               content::PAGE_TRANSITION_RELOAD);
 }
 
 void InfoBarDelegate::RemoveSelf() {
   if (owner_)
     owner_->RemoveInfoBar(this);  // Clears |owner_|.
 }