Fixed: <rdar://problem/3396872> ICONS: icon DB inconsistencies can cause slowness...

	Fixed: <rdar://problem/3396872> ICONS: icon DB inconsistencies can cause slowness during startup, idle and quit

        Reviewed by john.

        * Misc.subproj/WebFileDatabase.m:
        (-[WebFileDatabase objectForKey:]): added logging code
        * Misc.subproj/WebIconDatabase.m:
        (-[WebIconDatabase init]): use alloc, init rather than autorelease, retain
        (-[WebIconDatabase _loadIconDictionaries]): use 1 object for mapping icon URLs to site URLs and vice versa rather than 3. This avoids inconsistencies and is faster.
        (-[WebIconDatabase _updateFileDatabase]): write 1 object out

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@7970 268f45cc-cd09-0410-ab3c-d52691b4dbfc