Remove various Heap* types.

Remove various Heap* types.

Also removed a bunch of trace() methods which
I touched by accident.  Turns out they're
all very interconnected sadly.

I re-wrote Supplement to not use templates
in an earlier version of this patch
but hit some trouble with vtables
and decided to table that work
for a later time once more of oilpan
has been unwound.

R=abarth@chromium.org

Committed: https://chromium.googlesource.com/external/mojo/+/9564233315df4264901882bbf4e86b6417f9c68b

[abarth-chromium, 2014-10-28 01:19:16]

lgtm

[eseidel, 2014-10-28 01:19:51]

Committed patchset #1 (id:1) manually as
9564233315df4264901882bbf4e86b6417f9c68b.