Add Secure Context to EyeDropper API.

Per https://www.chromium.org/Home/chromium-security/prefer-secure-origins-for-powerful-new-features
it is recommended that new and particularly powerful web platform
features should be available only to secure origins by default.

Bug: 1253760
Change-Id: I72223ab7ae7b215c215534fba6103e5d0d2dde92
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3189871
Reviewed-by: Mason Freed <masonf@chromium.org>
Commit-Queue: Ionel Popescu <iopopesc@microsoft.com>
Cr-Commit-Position: refs/heads/main@{#925792}