Revert of Revert of Set defaultPageScaleLimits before setIgnoreViewportTagScaleLimits

Revert of Revert of Set defaultPageScaleLimits before setIgnoreViewportTagScaleLimits (patchset #1 id:1 of https://codereview.chromium.org/897173003/)

Reason for revert:
These aren't the changes you're looking for.

Original issue's description:
> Revert of Set defaultPageScaleLimits before setIgnoreViewportTagScaleLimits (patchset #2 id:20001 of https://codereview.chromium.org/860283005/)
>
> Reason for revert:
> Speculatively reverting to try to fix broken layout tests in Blink:
> compositing/iframes/iframe-composited-scrolling-hide-and-show.html
> compositing/iframes/overlapped-iframe-iframe.html
> svg/as-border-image/svg-as-border-image-2.html
> and more.
>
> Original issue's description:
> > Set defaultPageScaleLimits before setIgnoreViewportTagScaleLimits
> >
> > setIgnoreViewportTagScaleLimits copies the default limits into the UA
> > constraints. This was happening before the defualt limits were set during
> > initialization so it was clamping page scale at [1,1].
> >
> > BUG=453377
> >
> > Committed: https://crrev.com/ebbcc53e21fbfe15a76fa7fbf6d14c84095880ee
> > Cr-Commit-Position: refs/heads/master@{#314668}
>
> TBR=aelias@chromium.org,sievers@chromium.org,bokan@chromium.org
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> BUG=453377
>
> Committed: https://crrev.com/910b93d89932cc75fcce36f4dbc5f3bef7c2f064
> Cr-Commit-Position: refs/heads/master@{#314723}

TBR=aelias@chromium.org,bokan@chromium.org,sievers@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=453377
Committed: https://crrev.com/5ae8ca360d786b99258ef62e9ed11f281da0dcdc
Cr-Commit-Position: refs/heads/master@{#314747}

[dcheng, 2015-02-05 04:02:44]

Created Revert of Revert of Set defaultPageScaleLimits before
setIgnoreViewportTagScaleLimits

[commit-bot: I haz the power, 2015-02-05 04:03:20]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/900153002/1

[commit-bot: I haz the power, 2015-02-05 04:04:13]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-02-05 04:06:09]

Patchset 1 (id:??) landed as
https://crrev.com/5ae8ca360d786b99258ef62e9ed11f281da0dcdc
Cr-Commit-Position: refs/heads/master@{#314747}