Make maybeConvertNeutral pure virtual

Make maybeConvertNeutral pure virtual

The body of SVGInterpolationType::maybeConvertNeutral is NOTREACHED()
with a comment that the function must be overridden except in a particular
condition. This patch changes maybeConvertNeutral to be pure virtual and moves
the NOTREACHED implementation into SVGTransformListInterpolationType,
which is the only subclass that meets the specified condition. This brings this
function into line with the approach taken in
SVGInterpolationType::appliedSVGValue and crrev.com/1959993002.

Committed: https://crrev.com/09b25d538b2cd35b4c1c482fce20206d254d2736
Cr-Commit-Position: refs/heads/master@{#403116}

[suzyh_UTC10 (ex-contributor), 2016-06-30 01:14:42]

suzyh@chromium.org changed reviewers:
+ alancutter@chromium.org

[alancutter (OOO until 2018), 2016-06-30 04:31:19]

lgtm

[suzyh_UTC10 (ex-contributor), 2016-06-30 06:43:11]

The CQ bit was checked by suzyh@chromium.org

[commit-bot: I haz the power, 2016-06-30 06:43:32]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-06-30 08:05:29]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-06-30 08:08:07]

Description was changed from

==========
Make maybeConvertNeutral pure virtual

The body of SVGInterpolationType::maybeConvertNeutral is NOTREACHED()
with a comment that the function must be overridden except in a particular
condition. This patch changes maybeConvertNeutral to be pure virtual and moves
the NOTREACHED implementation into SVGTransformListInterpolationType,
which is the only subclass that meets the specified condition. This brings this
function into line with the approach taken in
SVGInterpolationType::appliedSVGValue and crrev.com/1959993002.
==========

to

==========
Make maybeConvertNeutral pure virtual

The body of SVGInterpolationType::maybeConvertNeutral is NOTREACHED()
with a comment that the function must be overridden except in a particular
condition. This patch changes maybeConvertNeutral to be pure virtual and moves
the NOTREACHED implementation into SVGTransformListInterpolationType,
which is the only subclass that meets the specified condition. This brings this
function into line with the approach taken in
SVGInterpolationType::appliedSVGValue and crrev.com/1959993002.

Committed: https://crrev.com/09b25d538b2cd35b4c1c482fce20206d254d2736
Cr-Commit-Position: refs/heads/master@{#403116}
==========

[commit-bot: I haz the power, 2016-06-30 08:08:08]

Patchset 1 (id:??) landed as
https://crrev.com/09b25d538b2cd35b4c1c482fce20206d254d2736
Cr-Commit-Position: refs/heads/master@{#403116}