Reland "Do not expose DocumentLoader's request and original request"

This reverts commit 1e7c01e72a53b2cbb050f336b4b48604af3abcaa.

Reason for revert: Was not the correct CL to revert

Original change's description:
> Revert "Do not expose DocumentLoader's request and original request"
> 
> This reverts commit 53a589aec52b701d134df33ae166d97f5084f49d.
> 
> Reason for revert: Believe this to be the cause of https://bugs.chromium.org/p/chromium/issues/detail?id=916829
> 
> Original change's description:
> > Do not expose DocumentLoader's request and original request
> > 
> > Once we stop using WebURLLoader for navigations, there would be
> > no Request in DocumentLoader. This patch removes some dependencies
> > on it from outside of DocumentLoader.
> > 
> > There are still some dependencies through WebDocumentLoader - these
> > will go later.
> > 
> > TBR=mmenke@chromium.org,rdevlin.cronin@chromium.org
> > 
> > Bug: 855189
> > Change-Id: I0c44d7627804286ccce3a6eac14fb7cd92321411
> > Reviewed-on: https://chromium-review.googlesource.com/c/1382506
> > Commit-Queue: Dmitry Gozman <dgozman@chromium.org>
> > Reviewed-by: Nate Chapin <japhet@chromium.org>
> > Cr-Commit-Position: refs/heads/master@{#617992}
> 
> TBR=dgozman@chromium.org,japhet@chromium.org
> 
> Change-Id: Ifb00b5a6b706243a50d8ef03c5cf71fefaaeacb0
> No-Presubmit: true
> No-Tree-Checks: true
> No-Try: true
> Bug: 855189
> Reviewed-on: https://chromium-review.googlesource.com/c/1385479
> Reviewed-by: CJ DiMeglio <lethalantidote@chromium.org>
> Commit-Queue: CJ DiMeglio <lethalantidote@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#618043}

TBR=dgozman@chromium.org,japhet@chromium.org,lethalantidote@chromium.org

Change-Id: I2e31ca1df6f0337ec5a2c59ba5740d63df02866f
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 855189
Reviewed-on: https://chromium-review.googlesource.com/c/1385480
Reviewed-by: CJ DiMeglio <lethalantidote@chromium.org>
Commit-Queue: CJ DiMeglio <lethalantidote@chromium.org>
Cr-Commit-Position: refs/heads/master@{#618047}
18 files changed