<rdar://problem/13196481> and https://bugs.webkit.org/show_bug.cgi?id=113422

Reviewed by Alexey Proskuryakov (and looked over by Geoff Garen).

Remove timer-based approach support code:
* NetworkProcess/NetworkResourceLoader.cpp:
(WebKit::NetworkResourceLoader::NetworkResourceLoader):
(WebKit::NetworkResourceLoader::abortInProgressLoad):
(WebKit::NetworkResourceLoader::didFinishLoading):
* NetworkProcess/NetworkResourceLoader.h:

Add an object to encapsulate monitoring a resource going in to the disk cache.
It listens for a callback on the cached response indicating it is disk backed
and also sets a timeout so we don't keep the monitor alive and waiting forever.
* NetworkProcess/mac/DiskCacheMonitor.h: Added.
(WebKit::DiskCacheMonitor::destinationID):
(WebKit::DiskCacheMonitor::connectionToWebProcess):
(WebKit::DiskCacheMonitor::resourceRequest):
* NetworkProcess/mac/DiskCacheMonitor.mm: Added.
(CFCachedURLResponseSetBecameFileBackedCallBackBlock):
(WebKit::monitorFileBackingStoreCreation):
(WebKit::DiskCacheMonitor::DiskCachingMonitor):
(WebKit::DiskCacheMonitor::connection):

Refactoring and monitor certain cached responses:
* NetworkProcess/mac/NetworkResourceLoaderMac.mm:
(CFCachedURLResponseGetMemMappedData):
(WebKit::NetworkResourceLoader::tryGetShareableHandleFromCFURLCachedResponse): Use CFCachedURLResponseGetMemMappedData
  to explicitly get an mem-mapped data object.
(WebKit::NetworkResourceLoader::tryGetShareableHandleForResource):
(WebKit::NetworkResourceLoader::willCacheResponseAsync): If the resource is over the minimum
  size then set up a disk caching monitor.

* WebKit2.xcodeproj/project.pbxproj:

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@147006 268f45cc-cd09-0410-ab3c-d52691b4dbfc