Reviewed by kocienda.

        * History.subproj/WebBackForwardList.m:
        * History.subproj/WebHistoryItem.h:
        * History.subproj/WebHistoryItem.m:
        * History.subproj/WebHistoryItemPrivate.h: Added.
        * WebCoreSupport.subproj/WebBridge.m:
        * WebKit.pbproj/project.pbxproj:
        * WebView.subproj/WebFramePrivate.m:

        Fixed 3123375.  Call SPI to release all pending page caches

        Reviewed by kocienda.

        * Test/PageLoadTestController.m:
        (-[PageLoadTestController anyWindowWillClose:]):
        * Test/PageLoadTestRunner.m:
        (-[PageLoadTestRunner closeBrowserWindowsAndFinishCheckingForWorldLeaks]):
        (-[PageLoadTestRunner checkForWorldLeaksSoon]):
        (-[PageLoadTestRunner checkForWorldLeaksNow]):
        (-[PageLoadTestRunner startTest]):


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@3007 268f45cc-cd09-0410-ab3c-d52691b4dbfc