Revert of Improve linearized pdf load/show time.

Revert of Improve linearized pdf load/show time. (patchset #5 id:80001 of https://codereview.chromium.org/2455403002/ )

Reason for revert:
Breaks loading of linearized Dynamic XFA documents. e.g. The 'Dynamic Form Sample' on https://www.idrsolutions.com/jpdfforms/xfa-html5-example-conversions/ breaks when loaded through the website. It loads correctly off of disk.

Original issue's description:
> Reland of Improve linearized pdf load/show time.
> 
> Original issue's description:
> > Improve linearized pdf load/show time.
> > Reduce Pdf Plugin's count of reconnects.
> > Add tests for PDFPlugin DocumentLoader.
> >
> > DocumentLoader was splitted into separate components, and missing tests was added for them.
> >
> > The main ideas in this CL are:
> >
> > 1) Do not reset browser initiated connection at start (includes case when we can use range requests), if we request data near current downloading position.
> > 2) Request as much data as we can on each request, and continue loading data using current range request. (like tape rewind)
> > 3) Isolate RangeRequest logic into DocumentLoader.  Method OnPendingRequestComplete is called, when we receive requested data (main connection, or Range connection). (like tape playing without rewing).
> > 4) Fill this logic by tests.
> >
> > Example URL:
> > http://www.major-landrover.ru/upload/attachments/f/9/f96aab07dab04ae89c8a509ec1ef2b31.pdf
> > Comparison of changes:
> > https://drive.google.com/file/d/0BzWfMBOuik2QNGg0SG93Y3lpUlE/view?usp=sharing
> >
> > Committed: https://crrev.com/7fd7423cdee0dba84faf480d10dd66dcb57110d9
> > Cr-Commit-Position: refs/heads/master@{#427752}
> 
> Original review:
> https://codereview.chromium.org/2349753003/
> 
> Committed: https://crrev.com/3704ccf02007dd912933abc3f3006159171bc41b
> Cr-Commit-Position: refs/heads/master@{#429514}

TBR=rsesek@chromium.org,thestig@chromium.org,art-snake@yandex-team.ru
# Not skipping CQ checks because original CL landed more than 1 days ago.

[dsinclair, 2016-12-05 18:29:42]

The CQ bit was checked by dsinclair@chromium.org

[dsinclair, 2016-12-05 18:29:42]

Created Revert of Improve linearized pdf load/show time.

[commit-bot: I haz the power, 2016-12-05 18:29:58]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-12-05 18:34:14]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-12-05 18:34:15]

Try jobs failed on following builders:
  android_cronet on master.tryserver.chromium.android (JOB_FAILED,
https://build.chromium.org/p/tryserver.chromium.android/builders/android_cron...)
  chromium_presubmit on master.tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/chromium_presub...)
  linux_chromium_chromeos_rel_ng on master.tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)
  mac_chromium_compile_dbg_ng on master.tryserver.chromium.mac (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.mac/builders/mac_chromium_comp...)
  mac_chromium_rel_ng on master.tryserver.chromium.mac (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.mac/builders/mac_chromium_rel_...)

[dsinclair, 2016-12-05 19:54:38]

The CQ bit was checked by dsinclair@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2016-12-05 19:55:30]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[dsinclair, 2016-12-05 19:55:54]

dsinclair@chromium.org changed reviewers:
+ tsepez@chomium.org

[dsinclair, 2016-12-05 19:55:55]

PTAL.

The first patchset is the raw revert, the second patch set fixes up the patch
errors.

[commit-bot: I haz the power, 2016-12-05 20:53:10]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-12-05 20:53:11]

Dry run: Try jobs failed on following builders:
  mac_chromium_rel_ng on master.tryserver.chromium.mac (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.mac/builders/mac_chromium_rel_...)

[dsinclair, 2016-12-06 17:00:43]

On 2016/12/05 20:53:11, commit-bot: I haz the power wrote:
> Dry run: Try jobs failed on following builders:
>   mac_chromium_rel_ng on master.tryserver.chromium.mac (JOB_FAILED,
>
http://build.chromium.org/p/tryserver.chromium.mac/builders/mac_chromium_rel_...)

Closing this. The Cl is intertwined with the redirect fix. Going to see if I can
figure out how to make dynamic XFA work with these changes.