Add a simple script to simulate BUILD file glob() expansion.

Add a simple script to simulate BUILD file glob() expansion.

This lets us test changes to BUILD.public.

This is not yet automated in any way.  My hope is to trigger it quietly via the presubmit for any CL that adds or removes a file, or changes BUILD.public.

BUG=skia:

Committed: https://skia.googlesource.com/skia/+/df5b7603d2d2bb3ec75cfbf235a672ee80cf8d3a

[mtklein, 2015-08-17 21:51:47]

mtklein@google.com changed reviewers:
+ benjaminwagner@google.com, mtklein@google.com

[mtklein, 2015-08-17 21:54:02]

+CC Melanie

[dogben, 2015-08-17 21:56:32]

lgtm

[mtklein, 2015-08-17 21:56:52]

The CQ bit was checked by mtklein@google.com

[commit-bot: I haz the power, 2015-08-17 21:57:03]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1290833003/60001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1290833003/60001

[hal.canary, 2015-08-17 21:57:15]

halcanary@google.com changed reviewers:
+ halcanary@google.com

[hal.canary, 2015-08-17 21:57:15]

style nit:  imports at the top.

[mtklein, 2015-08-17 21:59:45]

On 2015/08/17 21:57:15, Hal Canary wrote:
> style nit:  imports at the top.

This is sort of a weird one.  We want to avoid adding symbols as much as
possible so we don't accidentally inject something into BUILD.public.  Keeping
these imports either nested inside functions or after execfile() is semantically
useful here.

[commit-bot: I haz the power, 2015-08-17 22:03:01]

Committed patchset #4 (id:60001) as
https://skia.googlesource.com/skia/+/df5b7603d2d2bb3ec75cfbf235a672ee80cf8d3a