Require that heap collections are used over traceable elements.
While it is fully supported, having Blink GC heap collection objects
with elements not themselves being heap objects nor containing
references to such, is unnecessary. And arguably a sign that the code
is unintentionally using a heap collection.
Thus, add static_assert()s which prevent heap collections containing
no traceable references.
R=haraken
BUG=585328
Review URL: https://codereview.chromium.org/1912093002
Cr-Commit-Position: refs/heads/master@{#389435}
3 files changed
