Add a flag for safe_browsing::kTelemetryForApkDownloads on Android

Having this flag would make it easier to test this on official builds
before Finch rollout begins.

Bug: 907280
Change-Id: I72a0e6dd9e45fc049b76c54c2fb46f542cc98d74
Reviewed-on: https://chromium-review.googlesource.com/c/1406160
Commit-Queue: Varun Khaneja <vakh@chromium.org>
Reviewed-by: Daniel Rubery <drubery@chromium.org>
Reviewed-by: Avi Drissman <avi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#622243}
5 files changed