https://chromium-review.googlesource.com/c/chromium/src/+/963402 might help getting something at the end of g_browser_process->system_network_context_manager()

+mmenke who may have opinions as reviewer of that upcoming CL

+imcheng for DeviceDescriptionServiceTest

I wonder if we're going to need a full (testing?) NetworkContext for TestingBrowserProcess and/or TestingProfile.  My own preference would be just to do integration tests because of how bogus those two classes are, but that's presumably far from a universal opinion, given all the consumers of TestingProfile, at least (And converting them all would be a pain).

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/192b8c9d48bafefd01ab363d28564d14d87b6ab2

commit 192b8c9d48bafefd01ab363d28564d14d87b6ab2
Author: Gabriel Charette <gab@chromium.org>
Date: Wed Mar 21 21:16:00 2018

DCHECK that tasks are only posted to BrowserThreads after they were initialized

Posting is still allowed in the SHUTDOWN phase in production (will no-op
when after the thread is torn down as usual) but it is again disallowed
after BrowserThreadImpl::ResetGlobalsForTesting (i.e. after
~TestBrowserThreadBundle).

content/browser/browser_thread_impl.cc :
 - Core change to deny PostTask to uninitialized BrowserThreads
   (shutdown is fine). In practice this prevents posting before
   BrowserMainLoop::CreateThreads in production and outside the scope of
   a TestBrowserThreadBundle in tests (and after
   ~TestBrowserThreadBundle() which fully uninitializes after shutdown).

chrome/browser/chrome_content_browser_client.cc :
 - ChromeContentBrowserClient::SetApplicationLocale can happen
   synchronously if IO thread is not yet initialized (change check to
   reflect proper thread).

content/browser/loader/url_loader_factory_impl_unittest.cc :
 - Make sure TestBrowserThreadBundle outlives members as well.

content/browser/media/capture/desktop_capture_device.cc
chrome/browser/media/router/discovery/dial/dial_url_fetcher.cc
content/browser/media/capture/desktop_capture_device_unittest.cc :
 - crbug.com/823869

content/browser/net/network_quality_observer_impl_unittest.cc :
 - NetworkQualityObserverImpl's constructor uses BrowserThreads, would
   previously no-op and not break the test but this change brings it
   closer to testing the same code as in production

content/browser/renderer_host/media/render_frame_audio_input_stream_factory_unittest.cc
chrome/browser/ssl/ssl_error_handler_unittest.cc
chrome/browser/chromeos/login/signin_partition_manager_unittest.cc
content/browser/renderer_host/render_widget_host_view_mac_editcommand_helper_unittest.mm :
 - See inline comments


chrome/browser/component_updater/subresource_filter_component_installer_unittest.cc
chrome/browser/profiles/profile_shortcut_manager_unittest_win.cc :
 - Trivial upgrade from ScopedTaskEnvironment as some logic does use
   BrowserThreads.

Bug:  823797 , 823869
Change-Id: Iab99220606714362959a00820ecd46334eae7c8a
Reviewed-on: https://chromium-review.googlesource.com/970861
Reviewed-by: anthonyvd <anthonyvd@chromium.org>
Reviewed-by: Sergey Ulanov <sergeyu@chromium.org>
Reviewed-by: Wez <wez@chromium.org>
Reviewed-by: John Abd-El-Malek <jam@chromium.org>
Reviewed-by: Emily Stark <estark@chromium.org>
Reviewed-by: Matt Menke <mmenke@chromium.org>
Reviewed-by: Alexei Svitkine <asvitkine@chromium.org>
Reviewed-by: Emircan Uysaler <emircan@chromium.org>
Commit-Queue: Gabriel Charette <gab@chromium.org>
Cr-Commit-Position: refs/heads/master@{#544845}
[modify] https://crrev.com/192b8c9d48bafefd01ab363d28564d14d87b6ab2/chrome/browser/chrome_content_browser_client.cc
[modify] https://crrev.com/192b8c9d48bafefd01ab363d28564d14d87b6ab2/chrome/browser/chromeos/login/signin_partition_manager_unittest.cc
[modify] https://crrev.com/192b8c9d48bafefd01ab363d28564d14d87b6ab2/chrome/browser/component_updater/subresource_filter_component_installer_unittest.cc
[modify] https://crrev.com/192b8c9d48bafefd01ab363d28564d14d87b6ab2/chrome/browser/media/router/discovery/dial/dial_url_fetcher.cc
[modify] https://crrev.com/192b8c9d48bafefd01ab363d28564d14d87b6ab2/chrome/browser/profiles/profile_shortcut_manager_unittest_win.cc
[modify] https://crrev.com/192b8c9d48bafefd01ab363d28564d14d87b6ab2/chrome/browser/ssl/ssl_error_handler_unittest.cc
[modify] https://crrev.com/192b8c9d48bafefd01ab363d28564d14d87b6ab2/content/browser/browser_thread_impl.cc
[modify] https://crrev.com/192b8c9d48bafefd01ab363d28564d14d87b6ab2/content/browser/loader/url_loader_factory_impl_unittest.cc
[modify] https://crrev.com/192b8c9d48bafefd01ab363d28564d14d87b6ab2/content/browser/media/capture/desktop_capture_device.cc
[modify] https://crrev.com/192b8c9d48bafefd01ab363d28564d14d87b6ab2/content/browser/media/capture/desktop_capture_device_unittest.cc
[modify] https://crrev.com/192b8c9d48bafefd01ab363d28564d14d87b6ab2/content/browser/net/network_quality_observer_impl_unittest.cc
[modify] https://crrev.com/192b8c9d48bafefd01ab363d28564d14d87b6ab2/content/browser/renderer_host/media/render_frame_audio_input_stream_factory_unittest.cc
[modify] https://crrev.com/192b8c9d48bafefd01ab363d28564d14d87b6ab2/content/browser/renderer_host/render_widget_host_view_mac_editcommand_helper_unittest.mm