Revert "Speculative fix for WebRequest memory leak"

This reverts commit b8d7b695.

Reason for revert: This looks like it breaks Incognito/ExtensionWebRequestApiAuthRequiredTest.WebRequestAuthRequiredAsync/0
and
UserProfile/ExtensionWebRequestApiAuthRequiredTest.WebRequestAuthRequiredAsync/0
on ASan bots

Bug:1004250

Original change's description:
> Speculative fix for WebRequest memory leak
> 
> It seems the WebRequest is leaking InProgressRequest objects (see bug).
> We were not catching errors on the loader binding, which may have caused
> us to miss the errors.
> 
> Bug: 999681
> Change-Id: Iab30e74f6af4649548528feeddceeeb297b92e2d
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1772060
> Reviewed-by: Karan Bhatia <karandeepb@chromium.org>
> Commit-Queue: Clark DuVall <cduvall@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#696216}

TBR=karandeepb@chromium.org,cduvall@chromium.org

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug: 999681
Change-Id: I3943981a16f1ee4f7b3827c3a7272628010bd625
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1804477Reviewed-by: Ioana Pandele <ioanap@chromium.org>
Commit-Queue: Ioana Pandele <ioanap@chromium.org>
Cr-Commit-Position: refs/heads/master@{#696768}

extensions/browser/api/web_request/web_request_proxying_url_loader_factory.cc

@@ -91,10 +91,6 @@ WebRequestProxyingURLLoaderFactory::InProgressRequest::InProgressRequest(
       &WebRequestProxyingURLLoaderFactory::InProgressRequest::OnRequestError,
       weak_factory_.GetWeakPtr(),
       network::URLLoaderCompletionStatus(net::ERR_ABORTED)));
-  proxied_loader_binding_.set_connection_error_handler(base::BindOnce(
-      &WebRequestProxyingURLLoaderFactory::InProgressRequest::OnRequestError,
-      weak_factory_.GetWeakPtr(),
-      network::URLLoaderCompletionStatus(net::ERR_ABORTED)));
 }
 
 WebRequestProxyingURLLoaderFactory::InProgressRequest::~InProgressRequest() {