A few small tweaks based on further analysis of GoogleURLTracker:

chrome/browser/google/google_url_tracker.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/google/google_url_tracker.h"
 
 #include <vector>
 
 #include "base/bind.h"
 #include "base/command_line.h"
@@ skipping 68 matching lines @@
   content::OpenURLParams params(google_util::AppendGoogleLocaleParam(GURL(
       "https://www.google.com/support/chrome/bin/answer.py?answer=1618699")),
       content::Referrer(),
       (disposition == CURRENT_TAB) ? NEW_FOREGROUND_TAB : disposition,
       content::PAGE_TRANSITION_LINK, false);
   owner()->web_contents()->OpenURL(params);
   return false;
 }
 
 void GoogleURLTrackerInfoBarDelegate::Show() {
-  owner()->AddInfoBar(this);
   showing_ = true;
+  owner()->AddInfoBar(this);  // May delete |this| on failure!
 }
 
 void GoogleURLTrackerInfoBarDelegate::Close(bool redo_search) {
+  if (redo_search) {
+    // Re-do the user's search on the new domain.
+    url_canon::Replacements<char> replacements;
+    const std::string& host(new_google_url_.host());
+    replacements.SetHost(host.data(), url_parse::Component(0, host.length()));
+    GURL new_search_url(search_url_.ReplaceComponents(replacements));
+    if (new_search_url.is_valid()) {
+      content::OpenURLParams params(new_search_url, content::Referrer(),
+          CURRENT_TAB, content::PAGE_TRANSITION_GENERATED, false);
+      owner()->web_contents()->OpenURL(params);
+    }
+  }
+
   if (!showing_) {
     // We haven't been added to a tab, so just delete ourselves.
     delete this;
     return;
   }
 
   // Synchronously remove ourselves from the URL tracker's list, because the
   // RemoveInfoBar() call below may result in either a synchronous or an
   // asynchronous call back to InfoBarClosed(), and it's easier to handle when
   // we just guarantee the removal is synchronous.
   google_url_tracker_->InfoBarClosed(map_key_);
   google_url_tracker_ = NULL;
 
-  // If we were showing in a background tab that was then closed, we could have
-  // been leaked, and subsequently reached here due to
-  // GoogleURLTracker::CloseAllInfoBars().  In this case our owner is now NULL
-  // so we should just do nothing.
-  // TODO(pkasting): This can go away once the InfoBar ownership model is fixed
-  // so that infobars in background tabs don't leak on tab closure.
-  if (!owner())
-    return;
-
-  if (redo_search) {
-    // Re-do the user's search on the new domain.
-    url_canon::Replacements<char> replacements;
-    const std::string& host(new_google_url_.host());
-    replacements.SetHost(host.data(), url_parse::Component(0, host.length()));
-    GURL new_search_url(search_url_.ReplaceComponents(replacements));
-    if (new_search_url.is_valid()) {
-      content::OpenURLParams params(new_search_url, content::Referrer(),
-          CURRENT_TAB, content::PAGE_TRANSITION_GENERATED, false);
-      owner()->web_contents()->OpenURL(params);
-    }
-  }
-
-  owner()->RemoveInfoBar(this);
+  // If we're already animating closed, we won't have an owner.  Do nothing in
+  // this case.
+  // TODO(pkasting): For now, this can also happen if we were showing in a
+  // background tab that was then closed, in which case we'll have leaked and
+  // subsequently reached here due to GoogleURLTracker::CloseAllInfoBars().
+  // This case will no longer happen once infobars are refactored to own their
+  // delegates.
+  if (owner())
+    owner()->RemoveInfoBar(this);
 }
 
 GoogleURLTrackerInfoBarDelegate::~GoogleURLTrackerInfoBarDelegate() {
   if (google_url_tracker_)
     google_url_tracker_->InfoBarClosed(map_key_);
 }
 
 string16 GoogleURLTrackerInfoBarDelegate::GetMessageText() const {
   return l10n_util::GetStringFUTF16(IDS_GOOGLE_URL_TRACKER_INFOBAR_MESSAGE,
                                     GetHost(true), GetHost(false));
@@ skipping 313 matching lines @@
 
 void GoogleURLTracker::CloseAllInfoBars(bool redo_searches) {
   // Close all infobars, whether they've been added to tabs or not.
   while (!infobar_map_.empty())
     infobar_map_.begin()->second->Close(redo_searches);
 
   // Any registered listeners for NAV_ENTRY_COMMITTED and TAB_CLOSED are now
   // irrelevant as the associated infobars are gone.
   registrar_.RemoveAll();
 }