Add tests for trace wrappers

Add tests for trace wrappers

This cl adds very basic tests for general trace wrappers features. And enables TraceWrappables runtime enabled feature for tests!

LOG=no
BUG=468240
Committed: https://crrev.com/f7d5d042289c5fbe918348830917b888ec587272
Cr-Commit-Position: refs/heads/master@{#419298}

[Marcel Hlopko, 2016-09-02 07:39:34]

The CQ bit was checked by hlopko@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2016-09-02 07:39:50]

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

[Marcel Hlopko, 2016-09-02 07:44:33]

hlopko@chromium.org changed reviewers:
+ haraken@chromium.org

[Marcel Hlopko, 2016-09-02 07:44:34]

Ptal :) The aim of this cl is to cover some general trace wrappers features. In
the next cl I'll upload write barriers with some additional tests (also testing
TraceTraits and traceWrappers methods more). Thanks!

[Marcel Hlopko, 2016-09-02 07:45:55]

Description was changed from

==========
Add tests for trace wrappers

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

to

==========
Add tests for trace wrappers

This cl adds very basic tests for general trace wrappers features. And enables
TraceWrappables runtime enabled feature for tests!

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

[commit-bot: I haz the power, 2016-09-02 08:03:05]

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

[commit-bot: I haz the power, 2016-09-02 08:03:06]

Dry run: Try jobs failed on following builders:
  linux_chromium_chromeos_rel_ng on master.tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)

[Marcel Hlopko, 2016-09-02 09:07:27]

The CQ bit was checked by hlopko@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2016-09-02 09:07:35]

Dry run: 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, 2016-09-02 10:24:38]

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

[commit-bot: I haz the power, 2016-09-02 10:24:38]

Dry run: Exceeded global retry quota

[haraken, 2016-09-02 10:53:15]

Thanks for working on this! LGTM :)

https://codereview.chromium.org/2301213003/diff/20001/third_party/WebKit/Sour...
File third_party/WebKit/Source/bindings/core/v8/ScriptWrappableVisitor.h
(right):

https://codereview.chromium.org/2301213003/diff/20001/third_party/WebKit/Sour...
third_party/WebKit/Source/bindings/core/v8/ScriptWrappableVisitor.h:60: const
void* object() { return m_object; }

I'd rename this to rawObjectPointer or something.

https://codereview.chromium.org/2301213003/diff/20001/third_party/WebKit/Sour...
File third_party/WebKit/Source/bindings/core/v8/ScriptWrappableVisitorTest.cpp
(right):

https://codereview.chromium.org/2301213003/diff/20001/third_party/WebKit/Sour...
third_party/WebKit/Source/bindings/core/v8/ScriptWrappableVisitorTest.cpp:18:
ThreadHeap::collectGarbage(BlinkGC::NoHeapPointersOnStack, BlinkGC::GCWithSweep,
BlinkGC::ForcedGC);

Use collectAllGarbage to make sure that all garbage are collected.

https://codereview.chromium.org/2301213003/diff/20001/third_party/WebKit/Sour...
third_party/WebKit/Source/bindings/core/v8/ScriptWrappableVisitorTest.cpp:37:
v8::HandleScope handleScope(isolate);

You don't need to create a HandleScope since V8TestingScope creates it for you
:)

https://codereview.chromium.org/2301213003/diff/20001/third_party/WebKit/Sour...
File third_party/WebKit/Source/bindings/core/v8/V8GCController.cpp (right):

https://codereview.chromium.org/2301213003/diff/20001/third_party/WebKit/Sour...
third_party/WebKit/Source/bindings/core/v8/V8GCController.cpp:395: void
V8GCController::collectGarbage(v8::Isolate* isolate, bool onlyMinorGc)

onlyMinorGC

https://codereview.chromium.org/2301213003/diff/20001/third_party/WebKit/Sour...
third_party/WebKit/Source/bindings/core/v8/V8GCController.cpp:402:
v8String(isolate, (String) ("if (gc) gc(" + flag + ")")), isolate);

Use StringBuilder instead.

StringBuilder builder = "if (gc) gc(";
builder.append(onlyMinorGC ? "true" : "false");
builder.append(")");

https://codereview.chromium.org/2301213003/diff/20001/third_party/WebKit/Sour...
File third_party/WebKit/Source/core/testing/DeathAwareScriptWrappable.cpp
(right):

https://codereview.chromium.org/2301213003/diff/20001/third_party/WebKit/Sour...
third_party/WebKit/Source/core/testing/DeathAwareScriptWrappable.cpp:1: //
Copyright 2014 The Chromium Authors. All rights reserved.

2016

https://codereview.chromium.org/2301213003/diff/20001/third_party/WebKit/Sour...
File third_party/WebKit/Source/core/testing/DeathAwareScriptWrappable.h (right):

https://codereview.chromium.org/2301213003/diff/20001/third_party/WebKit/Sour...
third_party/WebKit/Source/core/testing/DeathAwareScriptWrappable.h:35: {

Shall we add DCHECK(!s_instance) (i.e., we're not yet observing anything)?

[Marcel Hlopko, 2016-09-02 12:12:40]

Incorporated comments, thanks!

https://codereview.chromium.org/2301213003/diff/20001/third_party/WebKit/Sour...
File third_party/WebKit/Source/bindings/core/v8/ScriptWrappableVisitor.h
(right):

https://codereview.chromium.org/2301213003/diff/20001/third_party/WebKit/Sour...
third_party/WebKit/Source/bindings/core/v8/ScriptWrappableVisitor.h:60: const
void* object() { return m_object; }
Done.

https://codereview.chromium.org/2301213003/diff/20001/third_party/WebKit/Sour...
File third_party/WebKit/Source/bindings/core/v8/ScriptWrappableVisitorTest.cpp
(right):

https://codereview.chromium.org/2301213003/diff/20001/third_party/WebKit/Sour...
third_party/WebKit/Source/bindings/core/v8/ScriptWrappableVisitorTest.cpp:18:
ThreadHeap::collectGarbage(BlinkGC::NoHeapPointersOnStack, BlinkGC::GCWithSweep,
BlinkGC::ForcedGC);
Done.

https://codereview.chromium.org/2301213003/diff/20001/third_party/WebKit/Sour...
third_party/WebKit/Source/bindings/core/v8/ScriptWrappableVisitorTest.cpp:37:
v8::HandleScope handleScope(isolate);
On 2016/09/02 at 10:53:14, haraken wrote:
> You don't need to create a HandleScope since V8TestingScope creates it for you
:)

I actually do, I want the scope to be discarded and assert that the object was
collected.

https://codereview.chromium.org/2301213003/diff/20001/third_party/WebKit/Sour...
File third_party/WebKit/Source/bindings/core/v8/V8GCController.cpp (right):

https://codereview.chromium.org/2301213003/diff/20001/third_party/WebKit/Sour...
third_party/WebKit/Source/bindings/core/v8/V8GCController.cpp:395: void
V8GCController::collectGarbage(v8::Isolate* isolate, bool onlyMinorGc)
Done.

https://codereview.chromium.org/2301213003/diff/20001/third_party/WebKit/Sour...
third_party/WebKit/Source/bindings/core/v8/V8GCController.cpp:402:
v8String(isolate, (String) ("if (gc) gc(" + flag + ")")), isolate);
Done.

https://codereview.chromium.org/2301213003/diff/20001/third_party/WebKit/Sour...
File third_party/WebKit/Source/core/testing/DeathAwareScriptWrappable.h (right):

https://codereview.chromium.org/2301213003/diff/20001/third_party/WebKit/Sour...
third_party/WebKit/Source/core/testing/DeathAwareScriptWrappable.h:35: {
> Shall we add DCHECK(!s_instance) (i.e., we're not yet observing anything)?

Cannot, it's a static variable, and is reused between tests.

[haraken, 2016-09-02 12:20:14]

On 2016/09/02 12:12:40, Marcel Hlopko wrote:
> Incorporated comments, thanks!
> 
>
https://codereview.chromium.org/2301213003/diff/20001/third_party/WebKit/Sour...
> File third_party/WebKit/Source/bindings/core/v8/ScriptWrappableVisitor.h
> (right):
> 
>
https://codereview.chromium.org/2301213003/diff/20001/third_party/WebKit/Sour...
> third_party/WebKit/Source/bindings/core/v8/ScriptWrappableVisitor.h:60: const
> void* object() { return m_object; }
> Done.
> 
>
https://codereview.chromium.org/2301213003/diff/20001/third_party/WebKit/Sour...
> File third_party/WebKit/Source/bindings/core/v8/ScriptWrappableVisitorTest.cpp
> (right):
> 
>
https://codereview.chromium.org/2301213003/diff/20001/third_party/WebKit/Sour...
> third_party/WebKit/Source/bindings/core/v8/ScriptWrappableVisitorTest.cpp:18:
> ThreadHeap::collectGarbage(BlinkGC::NoHeapPointersOnStack,
BlinkGC::GCWithSweep,
> BlinkGC::ForcedGC);
> Done.
> 
>
https://codereview.chromium.org/2301213003/diff/20001/third_party/WebKit/Sour...
> third_party/WebKit/Source/bindings/core/v8/ScriptWrappableVisitorTest.cpp:37:
> v8::HandleScope handleScope(isolate);
> On 2016/09/02 at 10:53:14, haraken wrote:
> > You don't need to create a HandleScope since V8TestingScope creates it for
you
> :)
> 
> I actually do, I want the scope to be discarded and assert that the object was
> collected.
> 
>
https://codereview.chromium.org/2301213003/diff/20001/third_party/WebKit/Sour...
> File third_party/WebKit/Source/bindings/core/v8/V8GCController.cpp (right):
> 
>
https://codereview.chromium.org/2301213003/diff/20001/third_party/WebKit/Sour...
> third_party/WebKit/Source/bindings/core/v8/V8GCController.cpp:395: void
> V8GCController::collectGarbage(v8::Isolate* isolate, bool onlyMinorGc)
> Done.
> 
>
https://codereview.chromium.org/2301213003/diff/20001/third_party/WebKit/Sour...
> third_party/WebKit/Source/bindings/core/v8/V8GCController.cpp:402:
> v8String(isolate, (String) ("if (gc) gc(" + flag + ")")), isolate);
> Done.
> 
>
https://codereview.chromium.org/2301213003/diff/20001/third_party/WebKit/Sour...
> File third_party/WebKit/Source/core/testing/DeathAwareScriptWrappable.h
(right):
> 
>
https://codereview.chromium.org/2301213003/diff/20001/third_party/WebKit/Sour...
> third_party/WebKit/Source/core/testing/DeathAwareScriptWrappable.h:35: {
> > Shall we add DCHECK(!s_instance) (i.e., we're not yet observing anything)?
> 
> Cannot, it's a static variable, and is reused between tests.

LGTM

[Michael Lippautz, 2016-09-02 18:54:31]

The CQ bit was checked by mlippautz@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2016-09-02 18:55:03]

Dry run: 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, 2016-09-02 20:13:43]

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

[commit-bot: I haz the power, 2016-09-02 20:13:44]

Dry run: Exceeded global retry quota

[Marcel Hlopko, 2016-09-05 06:57:39]

The CQ bit was checked by hlopko@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2016-09-05 06:57:51]

Dry run: 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, 2016-09-05 07:00:00]

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

[commit-bot: I haz the power, 2016-09-05 07:00:01]

Dry run: Try jobs failed on following builders:
  mac_chromium_rel_ng on master.tryserver.chromium.mac (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.mac/builders/mac_chromium_rel_...)

[Marcel Hlopko, 2016-09-05 09:07:14]

The CQ bit was checked by hlopko@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2016-09-05 09:07:19]

Dry run: 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, 2016-09-05 10:24:17]

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

[commit-bot: I haz the power, 2016-09-05 10:24:18]

Dry run: Exceeded global retry quota

[Marcel Hlopko, 2016-09-05 12:23:59]

The CQ bit was checked by hlopko@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2016-09-05 12:24:07]

Dry run: 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, 2016-09-05 13:41:05]

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

[commit-bot: I haz the power, 2016-09-05 13:41:06]

Dry run: Try jobs failed on following builders:
  mac_chromium_rel_ng on master.tryserver.chromium.mac (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.mac/builders/mac_chromium_rel_...)

[Marcel Hlopko, 2016-09-06 09:35:18]

The CQ bit was checked by hlopko@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2016-09-06 09:35:36]

Dry run: 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, 2016-09-06 09:37:24]

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

[commit-bot: I haz the power, 2016-09-06 09:37:25]

Dry run: Try jobs failed on following builders:
  mac_chromium_rel_ng on master.tryserver.chromium.mac (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.mac/builders/mac_chromium_rel_...)

[Marcel Hlopko, 2016-09-06 10:01:14]

The CQ bit was checked by hlopko@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2016-09-06 10:01:25]

Dry run: 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, 2016-09-06 11:07:30]

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

[commit-bot: I haz the power, 2016-09-06 11:07:31]

Dry run: Try jobs failed on following builders:
  mac_chromium_rel_ng on master.tryserver.chromium.mac (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.mac/builders/mac_chromium_rel_...)

[Marcel Hlopko, 2016-09-06 12:18:02]

The CQ bit was checked by hlopko@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2016-09-06 12:18:16]

Dry run: 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, 2016-09-06 14:32:32]

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

[commit-bot: I haz the power, 2016-09-06 14:32:33]

Dry run: Try jobs failed on following builders:
  win_chromium_rel_ng on master.tryserver.chromium.win (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.win/builders/win_chromium_rel_...)

[Marcel Hlopko, 2016-09-07 14:42:46]

The CQ bit was checked by hlopko@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2016-09-07 14:43:08]

Dry run: 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, 2016-09-07 14:45:36]

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

[commit-bot: I haz the power, 2016-09-07 14:45:37]

Dry run: Try jobs failed on following builders:
  mac_chromium_compile_dbg_ng on master.tryserver.chromium.mac (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.mac/builders/mac_chromium_comp...)
  mac_chromium_rel_ng on master.tryserver.chromium.mac (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.mac/builders/mac_chromium_rel_...)

[Marcel Hlopko, 2016-09-07 14:53:27]

The CQ bit was checked by hlopko@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2016-09-07 14:53:42]

Dry run: 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, 2016-09-07 15:53:50]

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

[commit-bot: I haz the power, 2016-09-07 15:53:51]

Dry run: Try jobs failed on following builders:
  linux_android_rel_ng on master.tryserver.chromium.android (JOB_FAILED,
https://build.chromium.org/p/tryserver.chromium.android/builders/linux_androi...)

[Marcel Hlopko, 2016-09-07 18:18:12]

The CQ bit was checked by hlopko@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2016-09-07 18:18:34]

Dry run: 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, 2016-09-07 19:24:58]

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

[commit-bot: I haz the power, 2016-09-07 19:24:59]

Dry run: Try jobs failed on following builders:
  linux_android_rel_ng on master.tryserver.chromium.android (JOB_FAILED,
https://build.chromium.org/p/tryserver.chromium.android/builders/linux_androi...)

[Marcel Hlopko, 2016-09-14 11:00:29]

The CQ bit was checked by hlopko@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2016-09-14 11:00:44]

Dry run: 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, 2016-09-14 11:57:04]

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

[commit-bot: I haz the power, 2016-09-14 11:57:05]

Dry run: Try jobs failed on following builders:
  linux_android_rel_ng on master.tryserver.chromium.android (JOB_FAILED,
https://build.chromium.org/p/tryserver.chromium.android/builders/linux_androi...)
  mac_chromium_rel_ng on master.tryserver.chromium.mac (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.mac/builders/mac_chromium_rel_...)

[Marcel Hlopko, 2016-09-14 13:51:50]

The CQ bit was checked by hlopko@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2016-09-14 13:52:06]

Dry run: 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, 2016-09-14 15:05:48]

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

[commit-bot: I haz the power, 2016-09-14 15:05:49]

Dry run: Try jobs failed on following builders:
  mac_chromium_rel_ng on master.tryserver.chromium.mac (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.mac/builders/mac_chromium_rel_...)

[Marcel Hlopko, 2016-09-15 09:24:56]

The CQ bit was checked by hlopko@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2016-09-15 09:25:11]

Dry run: 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, 2016-09-15 11:34:56]

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

[commit-bot: I haz the power, 2016-09-15 11:34:58]

Dry run: This issue passed the CQ dry run.

[Marcel Hlopko, 2016-09-16 17:21:45]

The CQ bit was checked by hlopko@chromium.org

[Marcel Hlopko, 2016-09-16 17:21:45]

The patchset sent to the CQ was uploaded after l-g-t-m from haraken@chromium.org
Link to the patchset: https://codereview.chromium.org/2301213003/#ps240001
(title: "Rebase")

[commit-bot: I haz the power, 2016-09-16 17:22:10]

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, 2016-09-16 17:33:46]

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

[commit-bot: I haz the power, 2016-09-16 17:33:47]

Try jobs failed on following builders:
  cast_shell_android on master.tryserver.chromium.android (JOB_FAILED,
https://build.chromium.org/p/tryserver.chromium.android/builders/cast_shell_a...)
  chromeos_amd64-generic_chromium_compile_only_ng on
master.tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/chromeos_amd64-...)

[Marcel Hlopko, 2016-09-16 18:45:34]

The CQ bit was checked by hlopko@chromium.org

[Marcel Hlopko, 2016-09-16 18:45:35]

The patchset sent to the CQ was uploaded after l-g-t-m from haraken@chromium.org
Link to the patchset: https://codereview.chromium.org/2301213003/#ps260001
(title: "Fix")

[commit-bot: I haz the power, 2016-09-16 18:46:10]

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, 2016-09-16 18:49:14]

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

[commit-bot: I haz the power, 2016-09-16 18:49:16]

Try jobs failed on following builders:
  ios-simulator on master.tryserver.chromium.mac (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.mac/builders/ios-simulator/bui...)
  mac_chromium_compile_dbg_ng on master.tryserver.chromium.mac (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.mac/builders/mac_chromium_comp...)
  mac_chromium_rel_ng on master.tryserver.chromium.mac (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.mac/builders/mac_chromium_rel_...)

[Marcel Hlopko, 2016-09-16 19:00:40]

The CQ bit was checked by hlopko@chromium.org

[Marcel Hlopko, 2016-09-16 19:00:41]

The patchset sent to the CQ was uploaded after l-g-t-m from haraken@chromium.org
Link to the patchset: https://codereview.chromium.org/2301213003/#ps280001
(title: "Rebase master")

[commit-bot: I haz the power, 2016-09-16 19:01:04]

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, 2016-09-16 22:20:17]

Committed patchset #15 (id:280001)

[commit-bot: I haz the power, 2016-09-16 22:22:05]

Description was changed from

==========
Add tests for trace wrappers

This cl adds very basic tests for general trace wrappers features. And enables
TraceWrappables runtime enabled feature for tests!

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

to

==========
Add tests for trace wrappers

This cl adds very basic tests for general trace wrappers features. And enables
TraceWrappables runtime enabled feature for tests!

LOG=no
BUG=468240

Committed: https://crrev.com/f7d5d042289c5fbe918348830917b888ec587272
Cr-Commit-Position: refs/heads/master@{#419298}
==========

[commit-bot: I haz the power, 2016-09-16 22:22:06]

Patchset 15 (id:??) landed as
https://crrev.com/f7d5d042289c5fbe918348830917b888ec587272
Cr-Commit-Position: refs/heads/master@{#419298}

[iclelland, 2016-09-19 13:35:10]

A revert of this CL (patchset #15 id:280001) has been created in
https://codereview.chromium.org/2350733002/ by iclelland@chromium.org.

The reason for reverting is: Sorry for the revert; this patch has (I believe)
caused the heap-snapshot-with-detached-dom-tree.html to start failing.

The very first failure in that test was in
https://build.chromium.org/p/chromium.webkit/builders/WebKit%20Linux%20Trusty...
-- immediately after this CL was committed.

Here is the flakiness dashboard result for that test:

https://test-results.appspot.com/dashboards/flakiness_dashboard.html#tests=in...

The test is failing occasionally with output like this:

    Test that all nodes from the detached DOM tree will get into one group in
the heap snapshot. Bug 107819.

     Took heap snapshot
    Parsed snapshot
    SUCCESS: found (Detached DOM trees)
    SUCCESS: found Detached DOM tree / 3 entries
    FAIL: unexpected DIV count: 1

Reverting this CL since it appears to be primarily about the tests..