Update V8 to version 5.6.171.

Update V8 to version 5.6.171.

Summary of changes available at:
https://chromium.googlesource.com/v8/v8/+log/c646c1cc..9d63c07f

Please follow these instructions for assigning/CC'ing issues:
https://github.com/v8/v8/wiki/Triaging%20issues

Please close rolling in case of a roll revert:
https://v8-roll.appspot.com/
This only works with a Google account.

CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_precise_blink_rel;master.tryserver.chromium.linux:linux_optional_gpu_tests_rel;master.tryserver.chromium.mac:mac_optional_gpu_tests_rel;master.tryserver.chromium.win:win_optional_gpu_tests_rel

TBR=hablich@chromium.org,machenbach@chromium.org,littledan@chromium.org,vogelheim@chromium.org

[v8-autoroll, 2016-10-28 13:32:02]

The CQ bit was checked by v8-autoroll@chromium.org

[commit-bot: I haz the power, 2016-10-28 13:32:23]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-10-28 14:44:04]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-10-28 14:44:05]

Try jobs failed on following builders:
  win_optional_gpu_tests_rel on master.tryserver.chromium.win (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.win/builders/win_optional_gpu_...)

[v8-autoroll, 2016-10-28 14:45:31]

The CQ bit was checked by v8-autoroll@chromium.org

[commit-bot: I haz the power, 2016-10-28 14:45:50]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-10-28 16:23:17]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-10-28 16:23:18]

Try jobs failed on following builders:
  win_optional_gpu_tests_rel on master.tryserver.chromium.win (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.win/builders/win_optional_gpu_...)

[v8-autoroll, 2016-10-28 16:30:27]

The CQ bit was checked by v8-autoroll@chromium.org

[commit-bot: I haz the power, 2016-10-28 16:30:53]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[Michael Achenbach, 2016-10-28 16:40:41]

This is blocked on only one commit:
https://chromium.googlesource.com/v8/v8/+/50a5853f0de1b23f2b41f07d4856397c838...

Has a bunch of GC related failures, e.g. I see in the logs:
Stack Trace:
********************************************************************************
	ChildEBP RetAddr  Args to Child              
	0028d7cc 60c7b9a6 0022054b 00000001 008edd20
chrome_child!v8::internal::IncrementalMarking::ProcessMarkingDeque+0x94
	0028d8e4 60c78c3f 0022054b 00000000 00000000
chrome_child!v8::internal::IncrementalMarking::Step+0x376
	0028d904 60c7bad8 60cab255 00010004 1e94ccc0
chrome_child!v8::internal::IncrementalMarking::AdvanceIncrementalMarkingOnAllocation+0xbf
	0028d908 60cab255 00010004 1e94ccc0 0000004c
chrome_child!v8::internal::IncrementalMarking::Observer::Step+0x8
	0028d928 60ca8b3a 000036ec 1e94cd0c 1e94ccc0
chrome_child!v8::internal::NewSpace::InlineAllocationStep+0x65
	0028d958 60c2cfa4 0000004c 00000000 0000004c
chrome_child!v8::internal::NewSpace::EnsureAllocation+0xca
	0028d974 60c2cc35 0028d9a4 0000004c 00934ca0
chrome_child!v8::internal::NewSpace::AllocateRawUnaligned+0x24
	0028d9b0 60c5cc4e 0028d9dc 0000004c 00000000
chrome_child!v8::internal::Heap::AllocateRaw+0x1b5
	0028d9cc 60c31552 0028d9f8 0000004c 00000000
chrome_child!v8::internal::Heap::AllocateFillerObject+0x1e

or

	Thread 0 (crashed)
  	 0  chrome!ProcessMarkingDeque [objects-inl.h : 4602 + 0x0]

or

 	RetAddr           : Args to Child                                             
             : Call Site
  	000007fe`e4f2fd30 : 00000085`bf080000 0000003e`6cd4e939 00000085`bf081a78
0000003e`04000000 : chrome_child!v8::internal::HeapObject::SizeFromMap+0x6
  	000007fe`e4f2da8c : 00000085`bf080000 00000085`bf0e36d1 00000000`0017cd20
00000085`bf0e36d1 :
chrome_child!v8::internal::MarkCompactCollector::PushBlack+0xa0
  	000007fe`e4f59530 : 0000003e`6cd4e950 00000000`02be7f20 0000003e`6cd4e960
00000085`bf0e36d1 :
chrome_child!v8::internal::MarkCompactCollector::MarkObject+0x11c
  	000007fe`e4f4d3b1 : 0000003e`6cd4e939 00000000`02be7f20 0000003e`6cd013a4
00000158`9d377d11 :
chrome_child!v8::internal::MarkCompactMarkingVisitor::VisitPointers+0xc0
  	000007fe`e4f51695 : 00000000`0017cea0 00000000`00100000 0000006c`11e02201
00000000`0017cea0 :
chrome_child!v8::internal::MarkCompactCollector::EmptyMarkingDeque+0x241
  	000007fe`e4f0f259 : 00000000`0daa66e0 00000000`0daa6c80 00000000`00000003
00000000`00000003 :
chrome_child!v8::internal::RootMarkingVisitor::MarkObjectByPointer+0xf5

[Michael Achenbach, 2016-10-28 16:44:00]

The CQ bit was unchecked by machenbach@chromium.org

[Michael Achenbach, 2016-10-28 16:44:29]

Closed rolling

[Michael Achenbach, 2016-10-28 16:48:09]

Reverted the change. Guess there's no point merging it in here as it becomes a
noop. Will just close this roll and roll forward as soon as revert becomes lkgr.

[Michael Hablich, 2016-10-28 18:13:35]

On 2016/10/28 16:48:09, machenbach (slow) wrote:
> Reverted the change. Guess there's no point merging it in here as it becomes a
> noop. Will just close this roll and roll forward as soon as revert becomes
lkgr.

Thanks