Move EmbedderHeapTracer::TracePrologue call to the beginning of full gc

Move EmbedderHeapTracer::TracePrologue call to the beginning of full gc

With cl https://codereview.chromium.org/2043033002 blink will add new wrappers
to its marking deque (and maintain this deque) so black allocated wrappers are
not a problem anymore. To limit the scope of when blink has to detect wrappers,
we need to tell blink when we start and when we end full gcs. For that we can
nicely use TracePrologue and TraceEpilogue.

LOG=no
BUG=468240
Committed: https://crrev.com/ac1587bb86708d800f8e7bd9a2d30f4c04c6f964
Cr-Commit-Position: refs/heads/master@{#36937}

[Marcel Hlopko, 2016-06-09 12:05:21]

hlopko@chromium.org changed reviewers:
+ hpayer@chromium.org, jochen@chromium.org, mlippautz@chromium.org,
ulan@chromium.org

[Marcel Hlopko, 2016-06-09 12:07:49]

Ptal. Are these truly the only 2 entry points to the full gc?

[Michael Lippautz, 2016-06-09 14:18:13]

Should be the only places for a full GC, yes.

https://codereview.chromium.org/2051103002/diff/20001/src/heap/mark-compact.cc
File src/heap/mark-compact.cc (right):

https://codereview.chromium.org/2051103002/diff/20001/src/heap/mark-compact.c...
src/heap/mark-compact.cc:865:
heap_->mark_compact_collector()->embedder_heap_tracer()->TracePrologue();
Since we might abort incremental marking (just above) we potentially call
TracePrologue() twice. Is this ok?

[Marcel Hlopko, 2016-06-09 14:33:19]

So I taught EmbedderHeapTracer how to abort :)

[Michael Lippautz, 2016-06-10 11:24:00]

lgtm from my side but please wait for one of the others too as I haven't been
following all your changes

[jochen (gone - plz use gerrit), 2016-06-13 15:23:00]

lgtm

[Marcel Hlopko, 2016-06-13 16:43:08]

The CQ bit was checked by hlopko@chromium.org

[commit-bot: I haz the power, 2016-06-13 16:43:15]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/2051103002/40001

[commit-bot: I haz the power, 2016-06-13 17:13:09]

Committed patchset #3 (id:40001)

[commit-bot: I haz the power, 2016-06-13 17:15:38]

Description was changed from

==========
Move EmbedderHeapTracer::TracePrologue call to the beginning of full gc

With cl https://codereview.chromium.org/2043033002 blink will add new wrappers
to its marking deque (and maintain this deque) so black allocated wrappers are
not a problem anymore. To limit the scope of when blink has to detect wrappers,
we need to tell blink when we start and when we end full gcs. For that we can
nicely use TracePrologue and TraceEpilogue.

LOG=no
BUG=468240
==========

to

==========
Move EmbedderHeapTracer::TracePrologue call to the beginning of full gc

With cl https://codereview.chromium.org/2043033002 blink will add new wrappers
to its marking deque (and maintain this deque) so black allocated wrappers are
not a problem anymore. To limit the scope of when blink has to detect wrappers,
we need to tell blink when we start and when we end full gcs. For that we can
nicely use TracePrologue and TraceEpilogue.

LOG=no
BUG=468240

Committed: https://crrev.com/ac1587bb86708d800f8e7bd9a2d30f4c04c6f964
Cr-Commit-Position: refs/heads/master@{#36937}
==========

[commit-bot: I haz the power, 2016-06-13 17:15:39]

Patchset 3 (id:??) landed as
https://crrev.com/ac1587bb86708d800f8e7bd9a2d30f4c04c6f964
Cr-Commit-Position: refs/heads/master@{#36937}