Generate getters/setters for shape-margin.

Currently, the shape-margin property is a 'storage_only' field, so
it has no generated public getters/setters. This patch changes it to an
'external' field so that its getters/setters can be generated as well.

Diff: https://gist.github.com/nainar/d696bdebcf5347bd1a96d77f5a253f6f/revisions

BUG=628043

Change-Id: I1d85de05b8c03f8353c162d5df436f58ef594124
Reviewed-on: https://chromium-review.googlesource.com/536216
Reviewed-by: Darren Shen <shend@chromium.org>
Commit-Queue: nainar <nainar@chromium.org>
Cr-Commit-Position: refs/heads/master@{#479625}
2 files changed