Improve @IntDef in Chrome/Android

This patch is aligning various @IntDef to some standard used with many other CLs:

1. @IntDef is first, @Retention second and related @interface third
2. NUM_ENTRIES declaring number of entries is not included into @IntDef
3. there is used @Retention(RetentionPolicy.SOURCE)

BUG=919666

Change-Id: I0a2e0600e09ec1919b83e7bafc7e4ff6698dfa9d
Reviewed-on: https://chromium-review.googlesource.com/c/1461041
Reviewed-by: Ted Choc <tedchoc@chromium.org>
Commit-Queue: Marcin Wiącek <marcin@mwiacek.com>
Cr-Commit-Position: refs/heads/master@{#631995}
8 files changed