Implement StorageManager::getValues
https://bugs.webkit.org/show_bug.cgi?id=114461

Reviewed by Beth Dakin.

Source/WebCore:

Expose the item hash map.

* storage/StorageMap.h:
(WebCore::StorageMap::items):

Source/WebKit2:

* UIProcess/Storage/StorageManager.cpp:
(WebKit::StorageManager::StorageArea::items):
(WebKit::StorageManager::getValues):
Return the items from the right storage area.

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@148231 268f45cc-cd09-0410-ab3c-d52691b4dbfc