mek, I saw you have touched ForeignFetchRequestHandler recently- would you have a clue who should own this? 

That backtrace makes no sense. There is really no way anything in a browsertest should ever be able to hit the ForeignFetchRequestHandler constructor. Nothing will have registered for foreign fetch so no handler will ever be created.

(the rest of that "backtrace" doesn't seem to make any sense either, none of those methods would normally be calling eachother, so no idea what resulted in such a corrupted stack...)

ok, thanks. Closing for now- bot seems to be more happy now. 

https://build.chromium.org/p/chromium.win/builders/Win7%20Tests%20%28dbg%29%281%29 shows the test is still flaky. Flakes every 1/4 build.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/8458e05a54ad72235f9329863ebb87307ace8291

commit 8458e05a54ad72235f9329863ebb87307ace8291
Author: kjellander <kjellander@chromium.org>
Date: Tue Jun 14 15:14:41 2016

Disable WebViewTest.InterstitialTeardownOnBrowserShutdown on Windows

The test has been flaky recently:
https://build.chromium.org/p/chromium.win/builders/Win7%20Tests%20%28dbg%29%281%29

[848:1216:0614/053522:FATAL:weak_ptr.h(220)] Check failed: get() != nullptr.
Backtrace:
	base::Pickle::Attachment::~Attachment [0x10064967+255016]
	base::Pickle::Attachment::~Attachment [0x100B36CB+577932]
	content::ContentRendererClient::GetImageSerializationProcessor [0x113D0F89+13853897]

BUG= 619508 
TBR=mek@chromium.org

Review-Url: https://codereview.chromium.org/2062063002
Cr-Commit-Position: refs/heads/master@{#399708}

[modify] https://crrev.com/8458e05a54ad72235f9329863ebb87307ace8291/chrome/browser/apps/guest_view/web_view_browsertest.cc

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/8458e05a54ad72235f9329863ebb87307ace8291

commit 8458e05a54ad72235f9329863ebb87307ace8291
Author: kjellander <kjellander@chromium.org>
Date: Tue Jun 14 15:14:41 2016

Disable WebViewTest.InterstitialTeardownOnBrowserShutdown on Windows

The test has been flaky recently:
https://build.chromium.org/p/chromium.win/builders/Win7%20Tests%20%28dbg%29%281%29

[848:1216:0614/053522:FATAL:weak_ptr.h(220)] Check failed: get() != nullptr.
Backtrace:
	base::Pickle::Attachment::~Attachment [0x10064967+255016]
	base::Pickle::Attachment::~Attachment [0x100B36CB+577932]
	content::ContentRendererClient::GetImageSerializationProcessor [0x113D0F89+13853897]

BUG= 619508 
TBR=mek@chromium.org

Review-Url: https://codereview.chromium.org/2062063002
Cr-Commit-Position: refs/heads/master@{#399708}

[modify] https://crrev.com/8458e05a54ad72235f9329863ebb87307ace8291/chrome/browser/apps/guest_view/web_view_browsertest.cc

mek@chromium.org: can you please have another look?

Again, I'm the wrong person for this bug. I'm not sure what you expect me to do. I don't know anything about the code/test in question. Anyone from src/chrome/browser/apps/guest_view/OWNERS would almost certainly be a better owner...

wjmaclean@chromium.org can you take a look?

Lucas, would you be able to look at this one?

This test failed also in Linux:

https://build.chromium.org/p/chromium.linux/builders/Linux%20Tests%20%28dbg%29%281%29/builds/55242/steps/browser_tests%20on%20Ubuntu-12.04/logs/WebViewTests_WebViewTest.InterstitialTeardownOnBrowserShutdown_0/text

WebViewTests/WebViewTest.InterstitialTeardownOnBrowserShutdown/0 (run #1):
[ RUN      ] WebViewTests/WebViewTest.InterstitialTeardownOnBrowserShutdown/0
Xlib:  extension "RANDR" missing on display ":9".
Xlib:  extension "RANDR" missing on display ":9".
[13739:13739:0630/211830:WARNING:audio_manager.cc(297)] Multiple instances of AudioManager detected
[13739:13739:0630/211830:WARNING:audio_manager.cc(271)] Multiple instances of AudioManager detected
[13739:13739:0630/211830:WARNING:password_store_factory.cc(250)] Using basic (unencrypted) store for password storage. See https://chromium.googlesource.com/chromium/src/+/master/docs/linux_password_storage.md for more information about password storage options.
LaunchProcess: failed to execvp:
xdg-desktop-menu
LaunchProcess: failed to execvp:
xdg-icon-resource
[13739:13887:0630/211831:WARNING:shell_integration_linux.cc(304)] Could not install icon chrome-epdhceakmbcjnemgoiacglkjbpimgngk-Default.png at size 512.
LaunchProcess: failed to execvp:
xdg-desktop-menu
[13739:13739:0630/211833:INFO:CONSOLE(6)] "embedder.loadGuest: 52588", source: chrome-extension://epdhceakmbcjnemgoiacglkjbpimgngk/embedder.js (6)
[13739:13739:0630/211833:INFO:CONSOLE(13)] "guestSrcHTTPS: https://localhost:52588/extensions/platform_apps/web_view/interstitial_teardown/https_page.html", source: chrome-extension://epdhceakmbcjnemgoiacglkjbpimgngk/embedder.js (13)
[13739:13891:0630/211835:WARNING:ipc_message_attachment_set.cc(57)] MessageAttachmentSet destroyed with unconsumed descriptors: 0/1
[13739:13739:0630/211835:FATAL:weak_ptr.h(232)] Check failed: get() != nullptr.
#0 0x7f0aa243cf2e base::debug::StackTrace::StackTrace()
#1 0x7f0aa24a1e2f logging::LogMessage::~LogMessage()
#2 0x7f0a996d517d base::WeakPtr<>::operator->()
#3 0x7f0a9a376c27 content::RenderWidgetHostViewGuest::OnSwapCompositorFrame()
#4 0x7f0a9a851454 content::RenderWidgetHostImpl::OnSwapCompositorFrame()
#5 0x7f0a9a8502e9 content::RenderWidgetHostImpl::OnMessageReceived()
#6 0x7f0a9a813153 content::RenderProcessHostImpl::OnMessageReceived()
#7 0x7f0a9862d688 IPC::ChannelProxy::Context::OnDispatchMessage()
#8 0x7f0a98631d76 _ZNK4base8internal15RunnableAdapterIMN3IPC12ChannelProxy7ContextEFvRKNS2_7MessageEEE3RunIRK13scoped_refptrIS4_EJS7_EEEvOT_DpOT0_
#9 0x7f0a98631c77 _ZN4base8internal12InvokeHelperILb0EvE8MakeItSoIRKNS0_15RunnableAdapterIMN3IPC12ChannelProxy7ContextEFvRKNS5_7MessageEEEEJRK13scoped_refptrIS7_ESA_EEEvOT_DpOT0_
#10 0x7f0a98631c23 _ZN4base8internal7InvokerINS0_9BindStateINS0_15RunnableAdapterIMN3IPC12ChannelProxy7ContextEFvRKNS4_7MessageEEEEJPS6_S9_EEEFvvEE7RunImplIRKSC_RKSt5tupleIJ13scoped_refptrIS6_ES7_EEJLm0ELm1EEEEvOT_OT0_NS_13IndexSequenceIJXspT1_EEEE
#11 0x7f0a9863193c _ZN4base8internal7InvokerINS0_9BindStateINS0_15RunnableAdapterIMN3IPC12ChannelProxy7ContextEFvRKNS4_7MessageEEEEJPS6_S9_EEEFvvEE3RunEPNS0_13BindStateBaseE
#12 0x7f0aa241d0fe base::Callback<>::Run()
#13 0x7f0aa2442a9e base::debug::TaskAnnotator::RunTask()
#14 0x7f0aa24bfb9c base::MessageLoop::RunTask()
#15 0x7f0aa24bfe38 base::MessageLoop::DeferOrRunPendingTask()
#16 0x7f0aa24c0092 base::MessageLoop::DoWork()
#17 0x7f0aa24d7e06 base::MessagePumpGlib::Run()
#18 0x7f0aa24bf58f base::MessageLoop::RunHandler()
#19 0x7f0aa25684d4 base::RunLoop::Run()
#20 0x000006ed0353 content::RunThisRunLoop()
#21 0x000006ed0427 content::RunAllPendingInMessageLoop()
#22 0x000003ec1ca2 InProcessBrowserTest::RunTestOnMainThreadLoop()
#23 0x0000016e19da content::BrowserTestBase::ProxyRunTestOnMainThreadLoop()
#24 0x0000009e07dd _ZNK4base8internal15RunnableAdapterIM24DevToolsBeforeUnloadTestFvvEE3RunIRK13scoped_refptrI53DevToolsBeforeUnloadTest_TestDockedDevToolsClose_TestEJEEEvOT_DpOT0_
#25 0x0000016e2c52 _ZN4base8internal12InvokeHelperILb0EvE8MakeItSoIRKNS0_15RunnableAdapterIMN7content15BrowserTestBaseEFvvEEEJRK13scoped_refptrIS6_EEEEvOT_DpOT0_
#26 0x0000016e2c12 _ZN4base8internal7InvokerINS0_9BindStateINS0_15RunnableAdapterIMN7content15BrowserTestBaseEFvvEEEJPS5_EEEFvvEE7RunImplIRKS8_RKSt5tupleIJ13scoped_refptrIS5_EEEJLm0EEEEvOT_OT0_NS_13IndexSequenceIJXspT1_EEEE
#27 0x0000016e2a3c _ZN4base8internal7InvokerINS0_9BindStateINS0_15RunnableAdapterIMN7content15BrowserTestBaseEFvvEEEJPS5_EEEFvvEE3RunEPNS0_13BindStateBaseE
#28 0x000000881a6e base::Callback<>::Run()
#29 0x00000498a032 ChromeBrowserMainParts::PreMainMessageLoopRunImpl()
#30 0x000004988b18 ChromeBrowserMainParts::PreMainMessageLoopRun()
#31 0x7f0a9a057761 content::BrowserMainLoop::PreMainMessageLoopRun()
#32 0x7f0a996dbf70 _ZNK4base8internal15RunnableAdapterIMN4mojo10BindingSetIN7content5mojom14ProcessControlEE7ElementEFvvEE3RunIPS8_JEEEvOT_DpOT0_
#33 0x7f0a9a05f502 _ZN4base8internal12InvokeHelperILb0EiE8MakeItSoIRKNS0_15RunnableAdapterIMN7content15BrowserMainLoopEFivEEEJPS6_EEEiOT_DpOT0_
#34 0x7f0a9a05f4c7 _ZN4base8internal7InvokerINS0_9BindStateINS0_15RunnableAdapterIMN7content15BrowserMainLoopEFivEEEJNS0_17UnretainedWrapperIS5_EEEEEFivEE7RunImplIRKS8_RKSt5tupleIJSA_EEJLm0EEEEiOT_OT0_NS_13IndexSequenceIJXspT1_EEEE
#35 0x7f0a9a05f42c _ZN4base8internal7InvokerINS0_9BindStateINS0_15RunnableAdapterIMN7content15BrowserMainLoopEFivEEEJNS0_17UnretainedWrapperIS5_EEEEEFivEE3RunEPNS0_13BindStateBaseE
#36 0x7f0a996cb97e base::Callback<>::Run()
#37 0x7f0a9aaae1eb content::StartupTaskRunner::RunAllTasksNow()
#38 0x7f0a9a0557be content::BrowserMainLoop::CreateStartupTasks()
#39 0x7f0a9a0615ed content::BrowserMainRunnerImpl::Initialize()
#40 0x7f0a9a051d3d content::BrowserMain()
#41 0x7f0a9bc70fe6 content::RunNamedProcessTypeMain()
#42 0x7f0a9bc73292 content::ContentMainRunnerImpl::Run()
#43 0x7f0a9bc700a2 content::ContentMain()
#44 0x0000016e1725 content::BrowserTestBase::SetUp()
#45 0x000003ec0475 InProcessBrowserTest::SetUp()
#46 0x00000142a95d ExtensionBrowserTest::SetUp()
#47 0x0000008724b8 WebViewTestBase::SetUp()
#48 0x00000103cbaa _ZN7testing8internal12InvokeHelperIvNSt3tr15tupleIJEEEE12InvokeMethodI14ServiceProcessMS7_FvvEEEvPT_T0_RKS4_
#49 0x000004d0b12e testing::internal::HandleExceptionsInMethodIfSupported<>()
#50 0x000004d000c3 testing::Test::Run()
#51 0x000004d008a8 testing::TestInfo::Run()
#52 0x000004d00e4a testing::TestCase::Run()
#53 0x000004d0619c testing::internal::UnitTestImpl::RunAllTests()
#54 0x00000103c18a _ZN7testing8internal12InvokeHelperIbNSt3tr15tupleIJEEEE12InvokeMethodI20MockServiceIPCServerMS7_FbvEEEbPT_T0_RKS4_
#55 0x000004d0c7be testing::internal::HandleExceptionsInMethodIfSupported<>()
#56 0x000004d05e3f testing::UnitTest::Run()
#57 0x0000016901f1 RUN_ALL_TESTS()
#58 0x00000168f292 base::TestSuite::Run()
#59 0x000003ea793c ChromeTestSuiteRunner::RunTestSuite()
#60 0x000003ea7a39 ChromeTestLauncherDelegate::RunTestSuite()
#61 0x000006ec5b02 content::LaunchTests()


I think you should check |guest_| in RenderWidgetHostViewGuest::OnSwapCompositorFrame().