Fix issues when PrerenderContents::Destroy() is called during TabContents destruction.

chrome/browser/prerender/prerender_manager_unittest.cc

 // 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.
 
 #include "base/memory/scoped_vector.h"
 #include "base/time.h"
 #include "chrome/browser/prerender/prerender_contents.h"
 #include "chrome/browser/prerender/prerender_manager.h"
 #include "content/browser/browser_thread.h"
 #include "content/browser/renderer_host/render_view_host.h"
@@ skipping 48 matching lines @@
   TestPrerenderManager()
       : PrerenderManager(NULL),
         time_(base::Time::Now()),
         time_ticks_(base::TimeTicks::Now()),
         next_prerender_contents_(NULL) {
     rate_limit_enabled_ = false;
   }
 
   virtual ~TestPrerenderManager() {
     if (next_prerender_contents()) {
-      next_prerender_contents()->set_final_status(
+      next_prerender_contents_.release()->Destroy(
           FINAL_STATUS_MANAGER_SHUTDOWN);
     }
     // Set the final status for all PrerenderContents with an expected final
     // status of FINAL_STATUS_USED.  These values are normally set when the
     // prerendered RVH is swapped into a tab, which doesn't happen in these
     // unit tests.
     for (ScopedVector<PrerenderContents>::iterator it =
              used_prerender_contents_.begin();
          it != used_prerender_contents_.end(); ++it) {
       (*it)->set_final_status(FINAL_STATUS_USED);
@@ skipping 444 matching lines @@
   DummyPrerenderContents* prerender_contents =
       prerender_manager()->CreateNextPrerenderContents(fragment_url,
                                                        FINAL_STATUS_USED);
   EXPECT_TRUE(prerender_manager()->AddSimplePreload(fragment_url));
   EXPECT_TRUE(prerender_contents->has_started());
   ASSERT_EQ(prerender_contents,
             prerender_manager()->GetEntry(other_fragment_url));
 }
 
 }  // namespace prerender