It is possible to get an older version of the previous page when navigating back. This can happen if the main resource load has not completed before navigating away from the page.
<rdar://problem/22500680>
Created attachment 260292 [details] patch
Comment on attachment 260292 [details] patch r=me.
Comment on attachment 260292 [details] patch Attachment 260292 [details] did not pass mac-wk2-ews (mac-wk2): Output: http://webkit-queues.webkit.org/results/126785 New failing tests: http/tests/w3c/dom/nodes/ParentNode-querySelector-All-xhtml.xhtml
Created attachment 260293 [details] Archive of layout-test-results from ews104 for mac-mavericks-wk2 The attached test failures were seen while running run-webkit-tests on the mac-wk2-ews. Bot: ews104 Port: mac-mavericks-wk2 Platform: Mac OS X 10.9.5
Failure looks like an unrelated flake in a new test.
Comment on attachment 260292 [details] patch Clearing flags on attachment: 260292 Committed r189177: <http://trac.webkit.org/changeset/189177>
All reviewed patches have been landed. Closing bug.
A test added for this fix is flaky, filed bug 149087.