The following CL seems potentially suspicious:

Extensions: Add ability to check host permissions for initiator as well.
Changed by	karandeepb@chromium.org
Changed at	2018-02-06 9:50 PM (PST)
Repository	https://chromium.googlesource.com/chromium/src
Branch	
Revision	ea2dc902c30310942f19faef732056a843767ef1
Comments
Extensions: Add ability to check host permissions for initiator as well.

This CL adds the ability to check for host permission access to both the request
url and its initiator. WebRequestPermissions::REQUIRE_HOST_PERMISSION is renamed
to WebRequestPermissions::REQUIRE_HOST_PERMISSION_FOR_URL and
WebRequestPermissions::REQUIRE_HOST_PERMISSION_FOR_URL_AND_INITIATOR is
introduced. This will subsequently be used to check access for the Declarative
Net Request API.

BUG= 777714 , 696822

Change-Id: I8ec9b08be1e8eb240e28328b7c254055e63005f3
Reviewed-on: https://chromium-review.googlesource.com/905405
Commit-Queue: Karan Bhatia <karandeepb@chromium.org>
Reviewed-by: Istiaque Ahmed <lazyboy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#534924}
Changed files
chrome/browser/extensions/api/web_request/web_request_permissions_unittest.cc
extensions/browser/api/declarative_webrequest/webrequest_action.cc
extensions/browser/api/web_request/web_request_api.cc
extensions/browser/api/web_request/web_request_permissions.cc
extensions/browser/api/web_request/web_request_permissions.h

Don't think the above CL should have introduced any behavior change. 

fsamuel@: Can https://chromium-review.googlesource.com/c/chromium/src/+/881831 be responsible?

It's highly unlikely because my CL only has an impact if the content of the ExtensionView crashes. Maybe a better question is whether we care about ExtensionView anymore?

+apacible@: Does media router still use extensionview? Maybe we can simply delete it?

[Extensions Triage]: fsamuel@: I don't really have much context about these tests. From https://test-results.appspot.com/dashboards/flakiness_dashboard.html#tests=ExtensionViewTests%2FExtensionViewLoadApiTest.QueuedLoadAPILoadOtherExtension%2F0%0AExtensionViewTests%2FExtensionViewLoadApiTest.QueuedLoadAPILoadOtherExtension%2F0%0A, it seems that the tests did start flaking only recently. I don't think my CL above introduced any behavior changes. And I can't seem to find any other suspects. Can you took a look?

Reproducing ExtensionViewLoadApiTest.LoadAPILoadOtherExtension failure is easy with the following, as it is flaky due to a race with the SwapOut_ACK which destroys the host-side objects for a renderer after navigation.

--- a/content/renderer/render_frame_impl.cc
+++ b/content/renderer/render_frame_impl.cc
@@ -2218,6 +2218,7 @@ void RenderFrameImpl::OnSwapOut(
   // Swap out and stop sending any IPC messages that are not ACKs.
   if (is_main_frame_)
     render_view_->SetSwappedOut(true);
+  base::PlatformThread::Sleep(base::TimeDelta::FromMilliseconds(333));

I tried to look at the test but it's no ordinary unit test. Can someone else try this and look?

Here's the failure.

[ RUN      ] ExtensionViewLoadApiTest.LoadAPILoadOtherExtension
[206599:206764:1105/143057.186712:ERROR:object_proxy.cc(621)] Failed to call method: org.freedesktop.Notifications.GetCapabilities: object_path= /org/freedesktop/Notifications: org.freedesktop.DBus.Error.ServiceUnknown: The name org.freedesktop.Notifications was not provided by any .service files
[206599:206599:1105/143057.191393:WARNING:password_store_factory.cc(261)] 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.
[206599:206599:1105/143057.368346:WARNING:gaia_auth_fetcher.cc(858)] Could not reach Google Accounts servers: errno -11
[206599:206599:1105/143058.358251:WARNING:gaia_auth_fetcher.cc(858)] Could not reach Google Accounts servers: errno -11
[206599:206599:1105/143058.477185:WARNING:render_frame_host_impl.cc(474)] InterfaceRequest was dropped, the document is no longer active: content.mojom.RendererAudioOutputStreamFactory
[206599:206599:1105/143058.477258:WARNING:render_frame_host_impl.cc(474)] InterfaceRequest was dropped, the document is no longer active: resource_coordinator.mojom.FrameCoordinationUnit
[206599:206599:1105/143058.499839:INFO:CONSOLE(6)] "assertion failed: chrome-extension://dppcjffonoklmpdmljnpdojmoaefcabf/data:text/html,<body>Two</body> != chrome-extension://pemeknaakobkocgmimdeamlcklioagkh/data:text/html,%3Cbody%3EOne%3C/body%3E", source: chrome-extension://gdloliindgbiccapnoiglhjmghmdaofi/main.js (6)
../../chrome/browser/apps/guest_view/extension_view/extension_view_browsertest.cc:73: Failure
Value of: done_listener.WaitUntilSatisfied()
  Actual: false
Expected: true
Stack trace:
#0 0x0000027b3d9c testing::internal::UnitTestImpl::CurrentOsStackTraceExceptTop()
#1 0x0000027b3769 testing::internal::AssertHelper::operator=()
#2 0x0000012d9643 ExtensionViewTest::TestHelper()
#3 0x0000012d9a03 ExtensionViewLoadApiTest::TestLoadApiHelper()
#4 0x0000012d9ce1 ExtensionViewLoadApiTest_LoadAPILoadOtherExtension_Test::RunTestOnMainThread()
#5 0x000003653d02 content::BrowserTestBase::ProxyRunTestOnMainThreadLoop()
#6 0x0000030a2fe6 ChromeBrowserMainParts::PreMainMessageLoopRunImpl()
#7 0x0000030a1c45 ChromeBrowserMainParts::PreMainMessageLoopRun()
#8 0x7f51046df56a content::BrowserMainLoop::PreMainMessageLoopRun()
#9 0x7f5104c26035 content::StartupTaskRunner::RunAllTasksNow()
#10 0x7f51046de0ae content::BrowserMainLoop::CreateStartupTasks()
#11 0x7f51046e21ed content::BrowserMainRunnerImpl::Initialize()
#12 0x7f51046db972 content::BrowserMain()
#13 0x7f5105223678 content::ContentMainRunnerImpl::RunServiceManager()
#14 0x7f5105223519 content::ContentMainRunnerImpl::Run()
#15 0x7f50f82743e9 service_manager::Main()
#16 0x7f5105221881 content::ContentMain()
#17 0x00000365385d content::BrowserTestBase::SetUp()
#18 0x00000303da92 InProcessBrowserTest::SetUp()

[206720:206720:1105/143058.672064:WARNING:x11_util.cc(1392)] X error received: serial 200, error_code 3 (BadWindow), request_code 4, minor_code 0 (Unknown)
[206599:206699:1105/143058.694838:WARNING:discardable_shared_memory_manager.cc(409)] Some MojoDiscardableSharedMemoryManagerImpls are still alive. They will be leaked.
[206599:206599:1105/143058.698270:WARNING:pref_notifier_impl.cc(23)] Pref observer found at shutdown.
[206599:206599:1105/143058.698294:WARNING:pref_notifier_impl.cc(23)] Pref observer found at shutdown.
[206599:207064:1105/143058.704913:WARNING:internal_linux.cc(64)] Failed to read /proc/206720/stat
[  FAILED  ] ExtensionViewLoadApiTest.LoadAPILoadOtherExtension, where TypeParam =  and GetParam() =  (3034 ms)

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/950cedec9605a2843d2f97fd1d683b94938341ad

commit 950cedec9605a2843d2f97fd1d683b94938341ad
Author: danakj <danakj@chromium.org>
Date: Mon Nov 05 20:46:22 2018

Disable flaky ExtensionViewLoadApiTest.LoadAPILoadOtherExtension test

Also the QueuedLoadAPILoadOtherExtension variant of the test.

TBR=fsamuel@chromium.org

Change-Id: I466de3d2236ed71d85136674b6ca2c48569be548
Bug: 810225
Reviewed-on: https://chromium-review.googlesource.com/c/1318436
Reviewed-by: danakj <danakj@chromium.org>
Commit-Queue: danakj <danakj@chromium.org>
Cr-Commit-Position: refs/heads/master@{#605449}
[modify] https://crrev.com/950cedec9605a2843d2f97fd1d683b94938341ad/chrome/browser/apps/guest_view/extension_view/extension_view_browsertest.cc