Correction: This issue is broken in M-63 series, below is manual regression range.

Good build: 63.0.3235.0 
Bad build: 63.0.3236.0 

You are probably looking for a change made after 507263 (known good), but no later than 507264 (first known bad).
CHANGELOG URL:
The script might not always return single CL as suspect as some perf builds might get missing due to failure.
  https://chromium.googlesource.com/chromium/src/+log/dcc89b40499917f2300c4698247ccab3e4a2e8a9..f26a1708bb062b3cde9bc04f7c213987cd85d7ed

Suspect: https://chromium.googlesource.com/chromium/src/+/f26a1708bb062b3cde9bc04f7c213987cd85d7ed

@paulirish: Kindly help to reassign, if your changes are not related to this issue.

NOTE: This issue is also reproducible on Mac and Linux OS.

Kindly review the attached screen-cast for reference.

Deleted: Actual behavior.mp4 2.8 MB

	Actual behavior.mp4 2.8 MB View Download

Deleted: Expected behavior.mp4 2.3 MB

	Expected behavior.mp4 2.3 MB View Download

Stack Trace for the provided crash id:
--------------------------------------
Thread 0 (id: 3824) CRASHED [EXCEPTION_ACCESS_VIOLATION_READ @ 0x00000000 ] MAGIC SIGNATURE THREAD
Stack Quality100%Show frame trust levels
0x63838a86	(chrome_child.dll -SkImage.cpp:216 )	SkImage::readPixels(SkPixmap const &,int,int,SkImage::CachingHint)
0x65d40a8b	(chrome_child.dll -InspectorAuditsAgent.cpp:93 )	blink::InspectorAuditsAgent::getEncodedResponse(WTF::String const &,WTF::String const &,blink::protocol::Maybe<double>,blink::protocol::Maybe<bool>,blink::protocol::Maybe<WTF::String> *,int *,int *)
0x63ca7701	(chrome_child.dll -Audits.cpp:119 )	blink::protocol::Audits::DispatcherImpl::getEncodedResponse(int,std::unique_ptr<blink::protocol::DictionaryValue,std::default_delete<blink::protocol::DictionaryValue> >,blink::protocol::ErrorSupport *)
0x63cd373a	(chrome_child.dll -Network.cpp:1893 )	blink::protocol::Network::DispatcherImpl::dispatch(int,WTF::String const &,std::unique_ptr<blink::protocol::DictionaryValue,std::default_delete<blink::protocol::DictionaryValue> >)
0x63ce436a	(chrome_child.dll -Protocol.cpp:822 )	blink::protocol::UberDispatcher::dispatch(std::unique_ptr<blink::protocol::Value,std::default_delete<blink::protocol::Value> >,int *,WTF::String *)
0x65d3a699	(chrome_child.dll -InspectorSession.cpp:84 )	blink::InspectorSession::DispatchProtocolMessage(WTF::String const &,WTF::String const &)
0x65c92efa	(chrome_child.dll -WebDevToolsAgentImpl.cpp:522 )	blink::WebDevToolsAgentImpl::DispatchMessageFromFrontend(int,WTF::String const &,WTF::String const &)
0x65c92d50	(chrome_child.dll -WebDevToolsAgentImpl.cpp:509 )	blink::WebDevToolsAgentImpl::DispatchOnInspectorBackend(int,int,blink::WebString const &,blink::WebString const &)
0x652b38eb	(chrome_child.dll -devtools_agent.cc:242 )	content::DevToolsAgent::OnDispatchOnInspectorBackend(int,int,std::basic_string<char,std::char_traits<char>,std::allocator<char> > const &,std::basic_string<char,std::char_traits<char>,std::allocator<char> > const &)
0x652b36ef	(chrome_child.dll -ipc_message_templates.h:145 )	IPC::MessageT<DevToolsAgentMsg_DispatchOnInspectorBackend_Meta,std::tuple<int,int,std::basic_string<char,std::char_traits<char>,std::allocator<char> >,std::basic_string<char,std::char_traits<char>,std::allocator<char> > >,void>::Dispatch<content::DevToolsAgent,content::DevToolsAgent,void,void (content::DevToolsAgent::*)(int, int, const std::basic_string<char,std::char_traits<char>,std::allocator<char> > &, const std::basic_string<char,std::char_traits<char>,std::allocator<char> > &) __attribute__((thiscall))>
0x633d5c25	(chrome_child.dll -devtools_agent.cc:105 )	content::DevToolsAgent::OnMessageReceived(IPC::Message const &)
0x633d425e	(chrome_child.dll -render_frame_impl.cc:1718 )	content::RenderFrameImpl::OnMessageReceived(IPC::Message const &)
0x6336e73a	(chrome_child.dll -message_router.cc:56 )	IPC::MessageRouter::RouteMessage(IPC::Message const &)
0x63349de8	(chrome_child.dll -ipc_channel_proxy.cc:321 )	IPC::ChannelProxy::Context::OnDispatchMessage(IPC::Message const &)
0x63349dc6	(chrome_child.dll -bind_internal.h:333 )	base::internal::Invoker<base::internal::BindState<void (extensions::AutomationMessageFilter::*)(const IPC::Message &) __attribute__((thiscall)),scoped_refptr<extensions::AutomationMessageFilter>,IPC::Message>,void ()>::Run
0x632f7d66	(chrome_child.dll -task_annotator.cc:55 )	base::debug::TaskAnnotator::RunTask(char const *,base::PendingTask *)
0x63330494	(chrome_child.dll -task_queue_manager.cc:535 )	blink::scheduler::TaskQueueManager::ProcessTaskFromWorkQueue(blink::scheduler::internal::WorkQueue *,bool,blink::scheduler::LazyNow,base::TimeTicks *)
0x6332f1d8	(chrome_child.dll -task_queue_manager.cc:323 )	blink::scheduler::TaskQueueManager::DoWork(bool)
0x6332f040	(chrome_child.dll -bind_internal.h:333 )	base::internal::Invoker<base::internal::BindState<void (gpu::GpuWatchdogThread::*)(bool) __attribute__((thiscall)),base::WeakPtr<gpu::GpuWatchdogThread>,bool>,void ()>::Run
0x632f7d66	(chrome_child.dll -task_annotator.cc:55 )	base::debug::TaskAnnotator::RunTask(char const *,base::PendingTask *)
0x64297b02	(chrome_child.dll -incoming_task_queue.cc:128 )	base::internal::IncomingTaskQueue::RunTask(base::PendingTask *)
0x632f77d5	(chrome_child.dll -message_loop.cc:394 )	base::MessageLoop::RunTask(base::PendingTask *)
0x64262baa	(chrome_child.dll -message_loop.cc:406 )	base::MessageLoop::DeferOrRunPendingTask(base::PendingTask)
0x632f2a1d	(chrome_child.dll -message_loop.cc:450 )	base::MessageLoop::DoWork()
0x632f2926	(chrome_child.dll -message_pump_default.cc:37 )	base::MessagePumpDefault::Run(base::MessagePump::Delegate *)
0x64262afe	(chrome_child.dll -message_loop.cc:345 )	base::MessageLoop::Run(bool)
0x632f26ed	(chrome_child.dll -run_loop.cc:114 )	base::RunLoop::Run()
0x632e4f13	(chrome_child.dll -renderer_main.cc:222 )	content::RendererMain(content::MainFunctionParams const &)
0x632e4caf	(chrome_child.dll -content_main_runner.cc:427 )	content::RunNamedProcessTypeMain(std::basic_string<char,std::char_traits<char>,std::allocator<char> > const &,content::MainFunctionParams const &,content::ContentMainDelegate *)
0x632ded39	(chrome_child.dll -content_main_runner.cc:705 )	content::ContentMainRunnerImpl::Run()
0x632c3922	(chrome_child.dll -main.cc:456 )	service_manager::Main(service_manager::MainParams const &)
0x632c35ff	(chrome_child.dll -content_main.cc:19 )	content::ContentMain(content::ContentMainParams const &)
0x632c1d47	(chrome_child.dll -chrome_main.cc:125 )	ChromeMain
0x00192ef3	(chrome.exe -main_dll_loader_win.cc:199 )	MainDllLoader::Launch(HINSTANCE__ *,base::TimeTicks)
0x00191464	(chrome.exe -chrome_exe_main_win.cc:230 )	wWinMain
0x0024e7c7	(chrome.exe -exe_common.inl:283 )	__scrt_common_main_seh
0x77923379	(kernel32.dll + 0x00013379 )	BaseThreadInitThunk
0x77e792e1	(ntdll.dll + 0x000392e1 )	__RtlUserThreadStart
0x77e792b4	(ntdll.dll + 0x000392b4 )	_RtlUserThreadStart

Adding Release blocker for this issue.Please remove if not the case.

Thank You!

Still we are able to reproduce the issue on Windows 7,Mac 10.12.6 & Ubuntu 14.04 using chrome latest Canary-64.0.3278.0	as per C#0.

paulirish@, As it is marked as stable blocker , could you please take a look and update the thread.

Thanks..!

Friendly ping to get an update on this issue.

Gentle ping!!

paulirish@@,
Still we are able to reproduce the issue on Windows 7 , Mac 10.12.6 & Ubuntu 14.04 using latest Canary-65.0.3290.0 as per C#0.
Could you please take a look as it is marked as stable blocker.

Thanks..!

Seems to be a result of the more performant optimized image checks, can be worked around by unchecking the Performance category.

Will look into what's causing the crash.

Seems to be the result of a resource served as a mime type asset mismatch but still passes the baseline sniffing checks, fix in progress.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/9df8050c30be27870697b71adf7631870932942a

commit 9df8050c30be27870697b71adf7631870932942a
Author: Patrick Hulce <phulce@chromium.org>
Date: Wed Dec 13 20:23:42 2017

DevTools: Handle invalid bitmaps in Audits.getEncodedResponse

BUG= 787701 

Change-Id: Ia3b5cac31c8559f8a3549853257a121360677fef
Reviewed-on: https://chromium-review.googlesource.com/823074
Commit-Queue: Patrick Hulce <phulce@chromium.org>
Reviewed-by: Andrey Kosyakov <caseq@chromium.org>
Cr-Commit-Position: refs/heads/master@{#523860}
[modify] https://crrev.com/9df8050c30be27870697b71adf7631870932942a/third_party/WebKit/LayoutTests/http/tests/inspector-protocol/audits/get-encoded-response-expected.txt
[modify] https://crrev.com/9df8050c30be27870697b71adf7631870932942a/third_party/WebKit/LayoutTests/http/tests/inspector-protocol/audits/get-encoded-response.js
[modify] https://crrev.com/9df8050c30be27870697b71adf7631870932942a/third_party/WebKit/Source/core/inspector/InspectorAuditsAgent.cpp

This bug requires manual review: M64 has already been promoted to the beta branch, so this requires manual review
Please contact the milestone owner if you have questions.
Owners: cmasso@(Android), cmasso@(iOS), kbleicher@(ChromeOS), abdulsyed@(Desktop)

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot

Is this well tested in Canary and verified? How safe is this merge overall?

It's been in past 2 Canary releases, and I've manually verified the specified site no longer crashes when being audited.

Change is a simple null pointer check and should be safe to merge.

Approving merge to M64. Branch:3282

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/b680e5f74ed2f537585a8523720be1727fa991a8

commit b680e5f74ed2f537585a8523720be1727fa991a8
Author: Patrick Hulce <phulce@chromium.org>
Date: Fri Dec 15 18:36:56 2017

DevTools: Handle invalid bitmaps in Audits.getEncodedResponse

BUG= 787701 

Change-Id: Ia3b5cac31c8559f8a3549853257a121360677fef
Reviewed-on: https://chromium-review.googlesource.com/823074
Commit-Queue: Patrick Hulce <phulce@chromium.org>
Reviewed-by: Andrey Kosyakov <caseq@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#523860}(cherry picked from commit 9df8050c30be27870697b71adf7631870932942a)
Reviewed-on: https://chromium-review.googlesource.com/830134
Reviewed-by: Patrick Hulce <phulce@chromium.org>
Cr-Commit-Position: refs/branch-heads/3282@{#241}
Cr-Branched-From: 5fdc0fab22ce7efd32532ee989b223fa12f8171e-refs/heads/master@{#520840}
[modify] https://crrev.com/b680e5f74ed2f537585a8523720be1727fa991a8/third_party/WebKit/LayoutTests/http/tests/inspector-protocol/audits/get-encoded-response-expected.txt
[modify] https://crrev.com/b680e5f74ed2f537585a8523720be1727fa991a8/third_party/WebKit/LayoutTests/http/tests/inspector-protocol/audits/get-encoded-response.js
[modify] https://crrev.com/b680e5f74ed2f537585a8523720be1727fa991a8/third_party/WebKit/Source/core/inspector/InspectorAuditsAgent.cpp