I need this method because of ActiveScriptWrappables, which have to be processed
at the atomic pause even for incremental solution, as there is no other way of
detecting when an object starts or stops being active than querying it.

LOG=no
BUG=468240

Review-Url: https://codereview.chromium.org/2065833003
Cr-Commit-Position: refs/heads/master@{#37062}