A few small tweaks based on further analysis of GoogleURLTracker:

chrome/browser/google/google_url_tracker.cc

Index: chrome/browser/google/google_url_tracker.cc
===================================================================
--- chrome/browser/google/google_url_tracker.cc	(revision 134398)
+++ chrome/browser/google/google_url_tracker.cc	(working copy)
@@ -86,11 +86,24 @@
 }
 
 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;
@@ -104,29 +117,15 @@
   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() {