Merge 104252 - Source/WebCore: IndexedDB: fix cursor prefetch crash

Merge 104252 - Source/WebCore: IndexedDB: fix cursor prefetch crash
http://crbug.com/108071
https://bugs.webkit.org/show_bug.cgi?id=75596

Reviewed by Tony Chang.

Test: storage/indexeddb/prefetch-bugfix-108071.html
Note: DumpRenderTree doesn't exercise the bug, it only occurs in
multi-process chromium.  The layout test will soon be run as a
chromium ui test: http://codereview.chromium.org/9108004

* storage/IDBCursorBackendImpl.cpp:
(WebCore::IDBCursorBackendImpl::IDBCursorBackendImpl):
(WebCore::IDBCursorBackendImpl::~IDBCursorBackendImpl): Destroy
cursors before their objectstores.
(WebCore::IDBCursorBackendImpl::prefetchReset): Don't run continue if
the cursor is closed.
(WebCore::IDBCursorBackendImpl::close): Set a closed flag.
* storage/IDBCursorBackendImpl.h:

LayoutTests: IndexedDB: fix cursor prefetch crash
https://bugs.webkit.org/show_bug.cgi?id=75596

Reviewed by Tony Chang.

* storage/indexeddb/prefetch-bugfix-108071-expected.txt: Added.
* storage/indexeddb/prefetch-bugfix-108071.html: Added.


TBR=dgrogan@chromium.org
Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=104310