Oilpan: Replace the positive heap-contains cache with a binary search tree of memory regions.

R=ager@chromium.org, wibling@chromium.org
BUG=419760

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=183139

Review URL: https://codereview.chromium.org/616483002

git-svn-id: svn://svn.chromium.org/blink/trunk@183184 bbb929c8-8fbe-4397-9dbb-9b2b20218538