Stop using MojoURLLoaderFactoryGetter.

https://crrev.com/2410333006/ introduced MojoURLLoaderFactoryGetter which is
passed from RenderProcessHostImpl to ServiceWorkerFetchDispatcher.
The MojoURLLoaderFactoryGette is created on the UI thread and holds a WeakPtr
of the RenderProcessHostImpl. And it is passed to IO thread.

But WeakPtr is not thread safe.
http://www.chromium.org/developers/design-documents/threading#base_WeakPtr_and_Cancellation

So this CL stops using MojoURLLoaderFactoryGette and changes
ServiceWorkerFetchDispatcher::MaybeStartNavigationPreload() to get the
ResourceMessageFilter from ResourceeRequestInfoImpl.

BUG=649558

Review-Url: https://codereview.chromium.org/2465813003
Cr-Commit-Position: refs/heads/master@{#429169}
17 files changed