Only exposes Badge API on secure contexts.

Previously, it was available on all pages, regardless of whether they
were considered secure. Policy for new web apis is to only expose them
in secure contexts.

Bug: 1013493
Change-Id: Id2c810309d4b21554b2ab11300d959a0bcf31102
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1855149
Commit-Queue: Jay Harris <harrisjay@chromium.org>
Commit-Queue: Matt Giuca <mgiuca@chromium.org>
Auto-Submit: Jay Harris <harrisjay@chromium.org>
Reviewed-by: Matt Giuca <mgiuca@chromium.org>
Cr-Commit-Position: refs/heads/master@{#704994}

third_party/blink/renderer/modules/badging/navigator_badge.idl

@@ -4,6 +4,7 @@
 
 // https://wicg.github.io/badging/
 [
+    SecureContext,
     RuntimeEnabled=Badging,
     ImplementedAs=NavigatorBadge
 ] partial interface Navigator {