Keep track of the history's page IDs to avoid navigating to a stale entry.

      This ensures that a race between an asynchronous back/forward and a navigation
in the renderer doesn't confuse NavigationController.

BUG=86758
TEST=RenderViewTest.IgnoreStaleNavigations
TEST=NavigationControllerTest.InPage_Replace

Review URL: http://codereview.chromium.org/7327014

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@92748 0039d316-1c4b-4281-b951-d872f2087c98