This is because we failed to parse the stacktrace:


[FATAL:Vector.h(1829)] Check failed: position <= size() (1 vs. 0)
#0 0x6175963d in logging::LogMessage::~LogMessage() base/logging.cc:581:29
#1 0x6c79e803 in void WTF::Vector<blink::Member<blink::AXObject>, 0u, blink::HeapAllocator>::insert<blink::Member<blink::AXObject> const&>(unsigned int, blink::Member<blink::AXObject> const&) third_party/WebKit/Source/platform/wtf/Vector.h:1829:3
#2 0x6c79e5ff in blink::AXNodeObject::InsertChild(blink::AXObject*, unsigned int) third_party/WebKit/Source/modules/accessibility/AXNodeObject.cpp:2143:17
#3 0x6c79e21d in blink::AXNodeObject::AddChildren() third_party/WebKit/Source/modules/accessibility/AXNodeObject.cpp:2112:7
#4 0x6c7ad7a7 in blink::AXObject::Children() third_party/WebKit/Source/modules/accessibility/AXObject.cpp:1766:3
#5 0x6c8c0dad in blink::WebAXObject::ChildAt(unsigned int) const third_party/WebKit/Source/modules/exported/WebAXObject.cpp:214:17
#6 0x6ccda8e5 in content::BlinkAXTreeSource::GetChildren(blink::WebAXObject, std::__ndk1::vector<blink::WebAXObject, std::__ndk1::allocator<blink::WebAXObject> >*) const content/renderer/accessibility/blink_ax_tree_source.cc:380:32
#7 0x6cce9369 in ui::AXTreeSerializer<blink::WebAXObject, content::AXContentNodeData, content::AXContentTreeData>::WalkAllDescendants(blink::WebAXObject) ui/accessibility/ax_tree_serializer.h:544:10
#8 0x6cce93ab in ui::AXTreeSerializer<blink::WebAXObject, content::AXContentNodeData, content::AXContentTreeData>::WalkAllDescendants(blink::WebAXObject) ui/accessibility/ax_tree_serializer.h:546:5
#9 0x6cce93ab in ui::AXTreeSerializer<blink::WebAXObject, content::AXContentNodeData, content::AXContentTreeData>::WalkAllDescendants(blink::WebAXObject) ui/accessibility/ax_tree_serializer.h:546:5
#10 0x6cce93ab in ui::AXTreeSerializer<blink::WebAXObject, content::AXContentNodeData, content::AXContentTreeData>::WalkAllDescendants(blink::WebAXObject) ui/accessibility/ax_tree_serializer.h:546:5

The following revision refers to this bug:
  https://chromium.googlesource.com/infra/infra/+/1de1f19b78d7b934275700e97e31357f4f6c87d8

commit 1de1f19b78d7b934275700e97e31357f4f6c87d8
Author: Sharu Jiang <katesonia@google.com>
Date: Thu Jan 18 21:38:57 2018

[Predator] Add CallStackDetector for Check failure crash.

Bug:  802843 
Change-Id: Iea52ac0c0473718d04b01afa595849d90a85c42c
Reviewed-on: https://chromium-review.googlesource.com/874725
Reviewed-by: Chan Li <chanli@chromium.org>
Commit-Queue: Sharu Jiang <katesonia@chromium.org>

[modify] https://crrev.com/1de1f19b78d7b934275700e97e31357f4f6c87d8/appengine/predator/analysis/test/callstack_detectors_test.py
[modify] https://crrev.com/1de1f19b78d7b934275700e97e31357f4f6c87d8/appengine/predator/analysis/clusterfuzz_parser.py
[modify] https://crrev.com/1de1f19b78d7b934275700e97e31357f4f6c87d8/appengine/predator/analysis/callstack_detectors.py

The following revision refers to this bug:
  https://chromium.googlesource.com/infra/infra/+/d0bcc76d243f2323e422c077f6423c7c3f187ceb

commit d0bcc76d243f2323e422c077f6423c7c3f187ceb
Author: Sharu Jiang <katesonia@google.com>
Date: Thu Jan 18 23:51:59 2018

[Predator] Return both android job type detector and check failure detector for android check failure crash.

For android check failure type of crash, the GetCallStackDetectors will only return the AndroidJobDetector instead of CheckFailureDetector. If a crash is both Check failure and on android platform, simply return both of the detectors.

Bug:  802843 
Change-Id: Ib54fd47baa3390db07cb1c18aaf6757676e5702d
Reviewed-on: https://chromium-review.googlesource.com/875233
Reviewed-by: Chan Li <chanli@chromium.org>
Commit-Queue: Sharu Jiang <katesonia@chromium.org>

[modify] https://crrev.com/d0bcc76d243f2323e422c077f6423c7c3f187ceb/appengine/predator/analysis/clusterfuzz_parser.py

The following revision refers to this bug:
  https://chromium.googlesource.com/infra/infra/+/d76658c020af82ea9808a891bcfea562d6a56dfe

commit d76658c020af82ea9808a891bcfea562d6a56dfe
Author: Sharu Jiang <katesonia@google.com>
Date: Fri Jan 19 00:02:27 2018

[Predator] Fix run-predator script.

If we pass crash_identifiers to predator.FindCulprit it will always get the analysis from the datatore, that means the run-predator.py scripts cannot run Predator can any local change.
Pass CrashAnalysis instead, so it won't affect the appengine app, and in the meantime we can test local change by ``run-predator.py``.

Bug:  802843 
Change-Id: I87ff6b2bead34549ff1735a28b7bb9da5f3d2851
Reviewed-on: https://chromium-review.googlesource.com/875183
Reviewed-by: Chan Li <chanli@chromium.org>
Commit-Queue: Sharu Jiang <katesonia@chromium.org>

[modify] https://crrev.com/d76658c020af82ea9808a891bcfea562d6a56dfe/appengine/predator/scripts/run_predator.py
[modify] https://crrev.com/d76658c020af82ea9808a891bcfea562d6a56dfe/appengine/predator/app/common/crash_pipeline.py
[modify] https://crrev.com/d76658c020af82ea9808a891bcfea562d6a56dfe/appengine/predator/app/common/predator_for_clusterfuzz.py
[modify] https://crrev.com/d76658c020af82ea9808a891bcfea562d6a56dfe/appengine/predator/app/common/test/predator_app_test.py
[modify] https://crrev.com/d76658c020af82ea9808a891bcfea562d6a56dfe/appengine/predator/app/common/predator_app.py
[modify] https://crrev.com/d76658c020af82ea9808a891bcfea562d6a56dfe/appengine/predator/app/common/test/predator_for_clusterfuzz_test.py