Enable ash shell and unit tests in GN build.

Enable ash shell and unit tests in GN build.

Update ash gyp files. There were some obsolete 'sources!' entries and a non-test file accidentally in the ash unittests sources.

workspace_backdrop_delegate.cc was duplicated in both ash and the unit tests target. Apparetcly this was done to make the component build work because it didn't have the export designation. The GN build detected this because it uses source_set instead of static_library which caught the duplicate symbol. This adds the export designation, removes the duplicate, and also adds ash_export.h to the sources list.

There were some warnings about superfluous const usage that surfaced. I assume this file isn't being compiled with chromium_code in the GYP build.

Committed: https://crrev.com/ea76f5f5c3d6e0f73876d040265ad121346e9f3d
Cr-Commit-Position: refs/heads/master@{#294030}

[brettw, 2014-09-09 17:04:22]

brettw@chromium.org changed reviewers:
+ beng@chromium.org

[Ben Goodger (Google), 2014-09-09 17:05:29]

ben@chromium.org changed reviewers:
+ ben@chromium.org
- beng@chromium.org

[Ben Goodger (Google), 2014-09-09 17:05:30]

lgtm

[brettw, 2014-09-09 19:48:31]

The CQ bit was checked by brettw@chromium.org

[commit-bot: I haz the power, 2014-09-09 19:58:24]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/brettw@chromium.org/551373005/40001

[brettw, 2014-09-09 20:48:14]

The CQ bit was checked by brettw@chromium.org

[commit-bot: I haz the power, 2014-09-09 20:58:24]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/brettw@chromium.org/551373005/60001

[commit-bot: I haz the power, 2014-09-09 23:16:00]

Committed patchset #4 (id:60001) as 519597424abbe8f828779a5d5d0bb16fab288670

[commit-bot: I haz the power, 2014-09-10 03:56:21]

Patchset 4 (id:??) landed as
https://crrev.com/ea76f5f5c3d6e0f73876d040265ad121346e9f3d
Cr-Commit-Position: refs/heads/master@{#294030}