Oilpan: add lazy tracing annotations to recursive objects.

Oilpan: add lazy tracing annotations to recursive objects.

To avoid excessively deep call chains if eagerly tracing RenderQuote,
ContainerNodes (via its Node member) or MemoryCacheEntry objects,
declare these as non-eagerly traceable.

R=haraken
BUG=420515
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=186774

[sof, 2014-12-05 06:20:38]

sigbjornf@opera.com changed reviewers:
+ oilpan-reviews@chromium.org

[sof, 2014-12-05 06:20:39]

Please take a look.

Eager tracing ran into the depth limit for these three objects when running
layout tests, so the annotations are worth adding.

If eager tracing becomes default, we could extend the plugin to warn of some
simple cases (direct recursion), and consider extending Visitor (and everything
below) with something like traceLazy(), and use it to head off the recursion
instead. But not for right now.

[haraken, 2014-12-05 15:13:47]

Mostly LG, but I'd prefer making a decision that we should go with always-eager
and enable it on trunk before applying more optimizations.

[sof, 2014-12-09 07:40:24]

On 2014/12/05 15:13:47, haraken wrote:
> Mostly LG, but I'd prefer making a decision that we should go with
always-eager
> and enable it on trunk before applying more optimizations.

Should we move ahead with this one now?

[haraken, 2014-12-09 08:15:36]

On 2014/12/09 07:40:24, sof wrote:
> On 2014/12/05 15:13:47, haraken wrote:
> > Mostly LG, but I'd prefer making a decision that we should go with
> always-eager
> > and enable it on trunk before applying more optimizations.
> 
> Should we move ahead with this one now?

LGTM

[sof, 2014-12-09 12:06:08]

The CQ bit was checked by sigbjornf@opera.com

[commit-bot: I haz the power, 2014-12-09 12:07:20]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/758073009/1

[commit-bot: I haz the power, 2014-12-09 13:17:54]

Committed patchset #1 (id:1) as
https://src.chromium.org/viewvc/blink?view=rev&revision=186774