GitLab

Move the mediaGalleries API out of extensions code and into apps
code. This includes the API implementation, schema definition, features
entries, and API permission info.

Bug: 877240

Change-Id: I8b750143cdcd36700f36d9da088ebaec4abd4cfe
Reviewed-on: https://chromium-review.googlesource.com/1255584Reviewed-by: Dominick Ng <dominickn@chromium.org>
Reviewed-by: Tommy Li <tommycli@chromium.org>
Commit-Queue: Devlin <rdevlin.cronin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#595866}