Revert "Add CHECK in Job::SetSpdyHttpStreamOrBidirectionalStreamImpl()."

This reverts commit 0e554b21.

Reason for revert: Two crash reports already on the morning of the new Canary.

Original change's description:
> Add CHECK in Job::SetSpdyHttpStreamOrBidirectionalStreamImpl().
> 
> Bug: 819101
> Change-Id: I6618354362d7454ad4ffa69d383ef739895932d4
> Reviewed-on: https://chromium-review.googlesource.com/990512
> Commit-Queue: Bence Béky <bnc@chromium.org>
> Reviewed-by: Ryan Hamilton <rch@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#547694}

TBR=rch@chromium.org,bnc@chromium.org

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

Bug: 828865
Change-Id: If00bd7afc74680126998cecefd67fe21201cdc13
Reviewed-on: https://chromium-review.googlesource.com/995852Reviewed-by: Bence Béky <bnc@chromium.org>
Commit-Queue: Bence Béky <bnc@chromium.org>
Cr-Commit-Position: refs/heads/master@{#548113}

net/http/http_stream_factory_impl_job.cc

@@ -1167,10 +1167,6 @@ int HttpStreamFactoryImpl::Job::SetSpdyHttpStreamOrBidirectionalStreamImpl(
     DCHECK(delegate_->websocket_handshake_stream_create_helper());
 
     if (!try_websocket_over_http2_) {
-      // TODO(bnc): Change to DCHECK once https://crbug.com/819101 is fixed.
-      CHECK(origin_url_.SchemeIs(url::kWsScheme));
-      CHECK(proxy_info_.is_https());
-
       // Plaintext WebSocket is not supported over HTTP/2 proxy,
       // see https://crbug.com/684681.
       return ERR_NOT_IMPLEMENTED;