The embedder can get notification when V8 heap size approaches the heap limit
and can extend the heap limit if needed using
- v8::Isolate::AddNearHeapLimitCallback
- v8::Isolate::RemoveNearHeapLimitCallback

This generalizes the exiting v8::debug::SetOutOfMemoryCallback API.

Bug: chromium:824214

Cq-Include-Trybots: luci.chromium.try:linux_chromium_rel_ng;master.tryserver.blink:linux_trusty_blink_rel
Change-Id: Ia444cb7efb6fe85c57fa3785e8fd1d8b654a5224
Reviewed-on: https://chromium-review.googlesource.com/979447
Commit-Queue: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#52238}