ASSERTION FAILED: m_history->provisionalItem() == m_requestedHistoryItem.get()
when navigating to an uncached subframe

Reviewed by Brady Eidson.

Source/WebCore:

Test: http/tests/navigation/post-frames-goback1-uncached.html

* loader/FrameLoader.cpp: (WebCore::FrameLoader::loadURLIntoChildFrame):
Set m_requestedHistoryItem in a code path that doesn't go through FrameLoader::loadItem.

* loader/HistoryController.cpp: (WebCore::HistoryController::restoreDocumentState):
Now that we always set m_requestedHistoryItem, there is no need to traverse frame
tree to see if this document is being loaded as part of b/f navigation (which was
add in bug 90870).

LayoutTests:

Added a nearly identical version of http/tests/navigation/post-frames-goback1.html
that checks what happens when navigating back to an uncached main resource.

* http/tests/navigation/post-frames-goback1-uncached-expected.txt: Added.
* http/tests/navigation/post-frames-goback1-uncached.html: Copied from LayoutTests/http/tests/navigation/post-frames-goback1.html.
* http/tests/navigation/resources/form-target-uncached.pl: Copied from LayoutTests/http/tests/navigation/resources/form-target.pl.


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@154306 268f45cc-cd09-0410-ab3c-d52691b4dbfc