Avoid corrupting the pending_entry when an unexpected navigation commits.

content/browser/tab_contents/navigation_controller_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/file_util.h"
 #include "base/path_service.h"
 #include "base/scoped_ptr.h"
 #include "base/stl_util-inl.h"
 #include "base/string_util.h"
 #include "base/utf_string_conversions.h"
@@ skipping 595 matching lines @@
 
   // Now start going back one to the second page. It will be pending.
   controller().GoBack();
   EXPECT_EQ(1, controller().pending_entry_index());
   EXPECT_EQ(2, controller().last_committed_entry_index());
 
   // Not synthesize a totally new back event to the first page. This will not
   // match the pending one.
   rvh()->SendNavigate(0, kUrl1);
 
-  // The navigation should not have affected the pending entry.
-  EXPECT_EQ(1, controller().pending_entry_index());
+  // The committed navigation should clear the pending entry.
+  EXPECT_EQ(-1, controller().pending_entry_index());
 
   // But the navigated entry should be the last committed.
   EXPECT_EQ(0, controller().last_committed_entry_index());
   EXPECT_EQ(kUrl1, controller().GetLastCommittedEntry()->url());
 }
 
 // Tests what happens when we navigate forward successfully.
 TEST_F(NavigationControllerTest, Forward) {
   TestNotificationTracker notifications;
   RegisterForAllNavNotifications(&notifications, &controller());
@@ skipping 1404 matching lines @@
   TabNavigation nav(0, url0, GURL(), string16(),
                     webkit_glue::CreateHistoryStateForURL(url0),
                     PageTransition::LINK);
   session_helper_.AssertNavigationEquals(nav,
                                          windows_[0]->tabs[0]->navigations[0]);
   nav.set_url(url2);
   session_helper_.AssertNavigationEquals(nav,
                                          windows_[0]->tabs[0]->navigations[1]);
 }
 */