Use Length for the stroke-width property in SVGLayoutStyle

Use Length for the stroke-width property in SVGLayoutStyle

Straight-forward if it hadn't been for the default value - "1" - which
does not interact well with the zoom (is not affected by it). To deal
with that, introduce a helper wrapper - UnzoomedLength - and use that
instead of a plain Length.
The animation framework is changed to use AnimatedLength and
LengthStyleInterpolation. This leaves AnimatedSVGLength and
SVGLengthStyleInterpolation unused, so they are removed.

BUG=461375
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=191544

[fs, 2015-03-06 17:52:04]

fs@opera.com changed reviewers:
+ ericwilligers@chromium.org, pdr@chromium.org, timloh@chromium.org

[fs, 2015-03-06 17:52:05]

I guess you know the drill by now ;-) - this is the last one though.

A bit more involved than I had hoped for (due to the non-zero/percentage initial
value), think it turned out reasonable anyway in the end.

+timloh in case there was a better option that failed to consider for the style
resolving part.

[pdr., 2015-03-06 18:47:08]

LGTM

@timloh, would you like to take a look too?

https://codereview.chromium.org/983103003/diff/40001/Source/core/layout/style...
File Source/core/layout/style/SVGLayoutStyleDefs.h (right):

https://codereview.chromium.org/983103003/diff/40001/Source/core/layout/style...
Source/core/layout/style/SVGLayoutStyleDefs.h:145: class UnzoomedLength {
Clever approach since it prevents us from comparing zoomed to unzoomed.

[Timothy Loh, 2015-03-08 23:29:25]

lgtm

[Eric Willigers, 2015-03-09 08:07:06]

lgtm

[fs, 2015-03-09 09:47:51]

The CQ bit was checked by fs@opera.com

[commit-bot: I haz the power, 2015-03-09 09:48:39]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/983103003/40001

[fs, 2015-03-09 11:21:58]

The CQ bit was unchecked by fs@opera.com

[fs, 2015-03-09 13:01:17]

The CQ bit was checked by fs@opera.com

[fs, 2015-03-09 13:01:18]

The patchset sent to the CQ was uploaded after l-g-t-m from pdr@chromium.org,
timloh@chromium.org, ericwilligers@chromium.org
Link to the patchset: https://codereview.chromium.org/983103003/#ps60001 (title:
"lengthSetterForProperty")

[commit-bot: I haz the power, 2015-03-09 13:02:01]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/983103003/60001

[commit-bot: I haz the power, 2015-03-09 13:19:26]

Committed patchset #4 (id:60001) as
https://src.chromium.org/viewvc/blink?view=rev&revision=191544