Revert "Revert of [oilpan]: Change marking to do precise roots first and conservative second. (http…

Revert "Revert of [oilpan]: Change marking to do precise roots first and conservative second. (https://codereview.chromium.org/405403003/)"

This reverts commit 765af3a45b15c4e5f65810c8ed8e20d44da04034.

AFAICT the CrossThreadPointerToOrphanedPage test was a bit flaky in the sense that the compiler was free to reuse the slot where the stackPtrValue was located after the RELEASE_ASSERT. However the test assumed the stackPtrValue was on the stack (to mimic a rogue integer value finding a dead object) when doing the conservative GC further down.
After my change to Heap::CollectGarbage it seemed the android compiler no longer kept the value around and hence the test started failing. I have now moved the RELEASE_ASSERT down to after the point where we do the conservative GC which makes the test pass on android again.

I uploaded the unfixed diff first and then a second diff (moved RELEASE_ASSERT) with the fix.

R=ager@chromium.org, erik.corry@gmail.com, haraken@chromium.org, oilpan-reviews@chromium.org, sigbjornf@opera.com, tkent@chromium.org, zerny@chromium.org
BUG=

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=178845

[haraken, 2014-07-24 14:09:17]

LGTM

[wibling-chromium, 2014-07-24 14:45:32]

The CQ bit was checked by wibling@chromium.org

[commit-bot: I haz the power, 2014-07-24 14:45:43]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/wibling@chromium.org/413133006/20001

[commit-bot: I haz the power, 2014-07-24 14:56:39]

Change committed as 178845

[Mads Ager (chromium), 2014-08-13 09:07:53]

A revert of this CL (patchset #2) has been created in
https://codereview.chromium.org/464253002/ by ager@chromium.org.

The reason for reverting is: This breaks strongification of ephemerons when
there are pointers on the stack. See:

https://codereview.chromium.org/461413002/

for details.
.