Revert of Add a scroll offset to PDF documents to account for the top material design toolbar.

Revert of Add a scroll offset to PDF documents to account for the top material design toolbar. (patchset #7 id:120001 of https://codereview.chromium.org/1255403002/ )

Reason for revert:
This patch breaks print preview.

BUG=516829
Original issue's description:
> Add a scroll offset to PDF documents to account for the top material design toolbar.
>
> Previously the toolbar in the material design PDF UI would always cover the top
> of pages when it was first loaded or when a page was navigated to using the
> page selector. Now we ensure that a blank region is left at the very top of
> the document when it is first loaded. This is the region that the toolbar
> covers, so the document is not obscured at all. When pages are navigated to, we
> ensure that the top of the selected page is always underneath the toolbar
> so that it is not obscured. The one exception to this is when in fit-to-page
> mode which causes the page to be zoomed to cover the entire screen, ignoring
> the toolbar. This is so that users can take advantaging of filling all of the
> screen real-estate with a page when that is what they want.
>
> This is implemented by initially scrolling the document to a negative offset
> (which is equal to the toolbar height). All subsequent scrolls are relative
> to this initial scroll. A few small bugs that assumed there was no blank space
> above the first page have also been fixed.
>
> BUG=439114
>
> Committed: https://crrev.com/daad0f1f879b13c8b55797ae5ce106d382283047
> Cr-Commit-Position: refs/heads/master@{#341685}

TBR=sammc@chromium.org,tsergeant@chromium.org,raymes@chromium.org
BUG=439114
Committed: https://crrev.com/0bb69c7f9ab18c6e79dd607ee6ab405231964dac
Cr-Commit-Position: refs/heads/master@{#341820}

[Vitaly Buka (NO REVIEWS), 2015-08-04 21:42:51]

Created Revert of Add a scroll offset to PDF documents to account for the top
material design toolbar.

[Vitaly Buka (NO REVIEWS), 2015-08-04 21:43:12]

The CQ bit was checked by vitalybuka@chromium.org

[commit-bot: I haz the power, 2015-08-04 21:44:19]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1267553004/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1267553004/1

[commit-bot: I haz the power, 2015-08-04 23:20:20]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-08-04 23:20:57]

Patchset 1 (id:??) landed as
https://crrev.com/0bb69c7f9ab18c6e79dd607ee6ab405231964dac
Cr-Commit-Position: refs/heads/master@{#341820}