Revert 241291 "Fix a long standing leak on cancellation of rende..."

Revert 241291 "Fix a long standing leak on cancellation of rende..."

This caused crashes elsewhere in the loading code.

BUG=27911
> Fix a long standing leak on cancellation of renderer-
> initiated URLRequests.  ResourceDispatcher was not calling
> peer->OnCompletedRequest on cancellation of async requests,
> despite it being expected by WebURLLoaderImpl::Context
> (The only ResourceLoaderBridge::Peer).
> 
> This shouldn't impact externally visible behavior at all,
> other than fixing the leak, because once
> WebURLLoaderImpl::Context::Cancel() is called, it will never
> call back into WebURLLoaderImpl.
> 
> BUG=328092
> 
> Review URL: https://codereview.chromium.org/113893007

TBR=mmenke@chromium.org

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=272998

[mmenke, 2014-05-27 18:11:27]

Committed patchset #1 manually as r272998.