Don't scale fixed container adjustment in pinch virtual viewport.

Don't scale fixed container adjustment in pinch virtual viewport.

In the current method of pinch-zoom, position: fixed elements stick to
the visual viewport (i.e. the screen). This means when the user pinch
zooms in, the viewport gets smaller so the fixed layers attached to the
right and bottom need an adjustment to keep them fixed to the screen.

In the new virtual viewport mode, the fixed elements stick to the layout
viewport, which doesn't change under scale so we no longer need to scale
this adjustment. Additionally, the adjustment that previously came from
pinch zooming is not needed at all.

BUG=420277
Committed: https://crrev.com/8273d966fa2217069d9d73fd58591a644be71843
Cr-Commit-Position: refs/heads/master@{#300625}

[bokan, 2014-10-09 18:25:28]

bokan@chromium.org changed reviewers:
+ aelias@chromium.org

[bokan, 2014-10-09 18:27:28]

bokan@chromium.org changed reviewers:
- aelias@chromium.org

[bokan, 2014-10-09 18:56:38]

bokan@chromium.org changed reviewers:
+ aelias@chromium.org

[bokan, 2014-10-09 18:56:38]

PTAL, I'll add a test and land this after the top controls patches land, since
they add some testing machinery I want to build on top of.

[aelias_OOO_until_Jul13, 2014-10-09 19:07:04]

Looks good, nice that this is getting simpler.  Description nit: we're still
performing an adjustment on the impl thread, we're just not scaling it.  So
please rename the patch to "Don't scale fixed container adjustment in pinch
virtual viewport."

[bokan, 2014-10-20 15:06:18]

Fixed description + added test, ptal.

[aelias_OOO_until_Jul13, 2014-10-21 22:03:22]

lgtm

[bokan, 2014-10-22 00:25:10]

The CQ bit was checked by bokan@chromium.org

[commit-bot: I haz the power, 2014-10-22 00:27:25]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/646623003/100001

[commit-bot: I haz the power, 2014-10-22 02:40:54]

Committed patchset #3 (id:100001)

[commit-bot: I haz the power, 2014-10-22 04:05:38]

Patchset 3 (id:??) landed as
https://crrev.com/8273d966fa2217069d9d73fd58591a644be71843
Cr-Commit-Position: refs/heads/master@{#300625}