[OnionSoup] Remove DispatchFetchEventParams.request_body_blob_ptrs

Previously, in case of S13nServiceWorker without NetworkService,
to transfer those Blob elements of network::ResourceRequestBody when
calling blink.mojom.ServiceWorker.DispatchFetchEvent(), additionally
ServiceWorkerSubresourceLoader prepares an array of BlobPtrInfo for
those Blob data and transfers it as
DispatchFetchEventParams.request_body_blob_ptrs.
Then ServiceWorkerContextClient gets it and puts it into a
blink::WebHTTPBody as part of WebServiceWorkerRequest to enter Blink.

However, we can see that DispatchFetchEventParams.request_body_blob_ptrs
is unnecessary to be passed through the Mojo call,
ServiceWorkerContextClient itself should be able to get these
information from the received network::ResourceRequestBody.
This CL lets ServiceWorkerContextClient do that and then removes
DispatchFetchEventParams.request_body_blob_ptrs.

crrev.com/c/1390323 relies on this CL to have ServiceWorkerContextClient
get those BlobPtrInfos from a network::ResourceRequestBody sent by
another fetch event dispatcher ServiceWorkerURLRequestJob.

BUG=911930
TBR=thestig@chromium.org
for trivial changes in base/threading/thread_restrictions.h

Change-Id: I383732b60329a9cd7c4204c7fbeedff10eee1990
Reviewed-on: https://chromium-review.googlesource.com/c/1390263
Reviewed-by: Leon Han <leon.han@intel.com>
Reviewed-by: Matt Falkenhagen <falken@chromium.org>
Reviewed-by: Kinuko Yasuda <kinuko@chromium.org>
Commit-Queue: Leon Han <leon.han@intel.com>
Cr-Commit-Position: refs/heads/master@{#618924}
5 files changed