Reviewed by Darin.

        Move management of cache groups to ApplicationCacheStorage. Also,
        application caches now start out with a null group and will have their group set
        when the cache has finished loading. 

        * loader/appcache/ApplicationCache.cpp:
        (WebCore::ApplicationCache::ApplicationCache):
        Initialize m_group to 0.
        
        (WebCore::ApplicationCache::~ApplicationCache):
        Null check the group.
        
        (WebCore::ApplicationCache::setGroup):
        New method for setting the group.
        
        * loader/appcache/ApplicationCache.h:        
        (WebCore::ApplicationCache::create):
        Remove the group argument.
        
        * loader/appcache/ApplicationCacheGroup.cpp:
        (WebCore::ApplicationCacheGroup::~ApplicationCacheGroup):
        Let the storage know that the cache group has been destroyed.
        
        (WebCore::ApplicationCacheGroup::cacheForMainRequest):
        Call into the storage.
        
        (WebCore::ApplicationCacheGroup::selectCache):
        Call into the storage.
        
        (WebCore::ApplicationCacheGroup::documentLoaderDestroyed):
        When there are no document loaders associated with the cache group,
        set the newest cache to 0.
        
        (WebCore::ApplicationCacheGroup::cacheDestroyed):
        Delete the group if there are no associated caches.
        
        (WebCore::ApplicationCacheGroup::setNewestCache):
        New method that will set the newest cache and associate the group with the cache.
        
        (WebCore::ApplicationCacheGroup::checkIfLoadIsComplete):
        Call setNewestCache instead.
        
        * loader/appcache/ApplicationCacheStorage.cpp:
        (WebCore::urlHostHash):
        Move host hash method here.
        
        (WebCore::ApplicationCacheStorage::findOrCreateCacheGroup):
        New method that finds a cache group with a given manifest URL or creates a new one.

        (WebCore::ApplicationCacheStorage::cacheGroupForURL):
        New method that returns a cache group for a given URL.
        
        (WebCore::ApplicationCacheStorage::cacheGroupDestroyed):
        When the cache group has been destroyed, remove it from the hash map.
        
        * loader/appcache/ApplicationCacheStorage.h:
        Add new methods.I b



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@32762 268f45cc-cd09-0410-ab3c-d52691b4dbfc