GitLab

Makes CallbackInterfaceBase and its subclasses use wrapper-tracing
to retain the underlying v8::Object.  Lets existing clients of
CallbackInterfaceBase, which don't support wrapper-tracing, use
V8PersistentCallbackInterface<T> instead.  The behavior and lifetime
shouldn't change.

Bug: 778580
Change-Id: If5db42a3b8cd5622de0576a920128a0b5ab0861f
Reviewed-on: https://chromium-review.googlesource.com/951163Reviewed-by: Hitoshi Yoshida <peria@chromium.org>
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Cr-Commit-Position: refs/heads/master@{#541728}