Base new scale on minimum-scale after orientation change.

Base new scale on minimum-scale after orientation change.

The previous width-ratio based logic was complicated, and behaves badly
in a particular scenario where the contents overflows past the
webmaster's specified minimum scale.  Replace it with some much simpler
logic that just maintains distance from minimum scale.  (In most cases
this behaves the same as before, because minimum scale is usually based
on the ratio of viewport width to contents width.)

NOTRY=true
BUG=395503
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=178608

[aelias_OOO_until_Jul13, 2014-07-21 23:34:55]

Hi Jared, PTAL.  This seems to work okay when I try it out locally, but let me
know if you know of any difficult scenarios where this simplified logic might
have a problem.

[jdduke (slow), 2014-07-22 00:12:06]

On 2014/07/21 23:34:55, aelias wrote:
> Hi Jared, PTAL.  This seems to work okay when I try it out locally, but let me
> know if you know of any difficult scenarios where this simplified logic might
> have a problem.

I think I might have tried simply preserving the relative page scale factor at
one point, but I don't recall why I abandoned that approach.  Anyhow, this lgtm.

[aelias_OOO_until_Jul13, 2014-07-22 00:17:03]

The CQ bit was checked by aelias@chromium.org

[commit-bot: I haz the power, 2014-07-22 00:17:47]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/aelias@chromium.org/405263002/40001

[commit-bot: I haz the power, 2014-07-22 00:55:22]

FYI, CQ is re-trying this CL (attempt #1).
The failing builders are:
  win_gpu_triggered_tests on tryserver.chromium.gpu
(http://build.chromium.org/p/tryserver.chromium.gpu/builders/win_gpu_triggered...)

[commit-bot: I haz the power, 2014-07-22 01:29:40]

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

[commit-bot: I haz the power, 2014-07-22 01:29:41]

Try jobs failed on following builders:
  win_gpu_triggered_tests on tryserver.chromium.gpu
(http://build.chromium.org/p/tryserver.chromium.gpu/builders/win_gpu_triggered...)

[aelias_OOO_until_Jul13, 2014-07-22 01:34:31]

The CQ bit was checked by aelias@chromium.org

[commit-bot: I haz the power, 2014-07-22 01:35:12]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/aelias@chromium.org/405263002/40001

[commit-bot: I haz the power, 2014-07-22 01:36:46]

Change committed as 178608