The aura-mus conversion (https://codereview.chromium.org/2578893003) comes up as the bisect commit. Now to figure out why.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/9e38764793efdaef079e7ece7028ee84a9482a63

commit 9e38764793efdaef079e7ece7028ee84a9482a63
Author: erg <erg@chromium.org>
Date: Fri Mar 10 22:38:39 2017

aura-mus: wire up drag and drop.

- Drag now works again.
- Ensure the nested run loop gets torn down on errors.
- Adds logs of dvlogs for debugging when needed.
- Moves registration of aura components to //ui/aura/.

BUG= 699235 , 665077 

Review-Url: https://codereview.chromium.org/2739213003
Cr-Commit-Position: refs/heads/master@{#456193}

[modify] https://crrev.com/9e38764793efdaef079e7ece7028ee84a9482a63/services/ui/ws/drag_controller.cc
[modify] https://crrev.com/9e38764793efdaef079e7ece7028ee84a9482a63/services/ui/ws/drag_controller.h
[modify] https://crrev.com/9e38764793efdaef079e7ece7028ee84a9482a63/services/ui/ws/window_tree.cc
[modify] https://crrev.com/9e38764793efdaef079e7ece7028ee84a9482a63/ui/aura/env.cc
[modify] https://crrev.com/9e38764793efdaef079e7ece7028ee84a9482a63/ui/aura/env.h
[modify] https://crrev.com/9e38764793efdaef079e7ece7028ee84a9482a63/ui/aura/mus/drag_drop_controller_mus.cc
[modify] https://crrev.com/9e38764793efdaef079e7ece7028ee84a9482a63/ui/aura/mus/window_port_mus.cc
[modify] https://crrev.com/9e38764793efdaef079e7ece7028ee84a9482a63/ui/aura/mus/window_port_mus.h
[modify] https://crrev.com/9e38764793efdaef079e7ece7028ee84a9482a63/ui/aura/mus/window_tree_client.cc
[modify] https://crrev.com/9e38764793efdaef079e7ece7028ee84a9482a63/ui/aura/mus/window_tree_client.h
[modify] https://crrev.com/9e38764793efdaef079e7ece7028ee84a9482a63/ui/views/mus/desktop_window_tree_host_mus.cc
[modify] https://crrev.com/9e38764793efdaef079e7ece7028ee84a9482a63/ui/views/mus/mus_client.cc
[modify] https://crrev.com/9e38764793efdaef079e7ece7028ee84a9482a63/ui/views/mus/mus_client.h

I'm leaving this bug open since the previous patch didn't have unit tests because we don't have a way of scripting events in multiprocess mus unit tests yet. Once that's done, I can add some tests here and then this will be really done (in a way that hopefully won't regress this bad again).

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/f4153114859e218c8fe5bef9293f2ec07d9bd276

commit f4153114859e218c8fe5bef9293f2ec07d9bd276
Author: erg <erg@chromium.org>
Date: Sat Mar 18 02:41:15 2017

aura-mus: Fix regression and add tests for drag and drop,

This fixes a regression in drag and drop from last week where the use of
WindowTreeClients in nested RunLoops caused messages to not be delivered
from the window server, leading to drags never terminating, even after
releasing the mouse button.

This also adds an interactive ui tests which exercises the entire drag
pipeline from the client side in a test against a real instance of the
window server.

This also fixes the test window manager so that it responds to windows
requesting that their bounds be changed.

This also fixes how we initialize the OSDragExchangeProviderFactory. Env
can be switched from local aura mode to mus mode after initialization in
tests, and we have to handle that case, otherwise any test which
interacts with drag and drop crashes.

BUG= 699235 

Review-Url: https://codereview.chromium.org/2759463002
Cr-Commit-Position: refs/heads/master@{#457935}

[modify] https://crrev.com/f4153114859e218c8fe5bef9293f2ec07d9bd276/services/ui/public/interfaces/window_server_test.mojom
[modify] https://crrev.com/f4153114859e218c8fe5bef9293f2ec07d9bd276/services/ui/test_wm/test_wm.cc
[modify] https://crrev.com/f4153114859e218c8fe5bef9293f2ec07d9bd276/services/ui/ws/window_server_test_impl.cc
[modify] https://crrev.com/f4153114859e218c8fe5bef9293f2ec07d9bd276/services/ui/ws/window_server_test_impl.h
[modify] https://crrev.com/f4153114859e218c8fe5bef9293f2ec07d9bd276/services/ui/ws/window_tree.cc
[modify] https://crrev.com/f4153114859e218c8fe5bef9293f2ec07d9bd276/ui/aura/env.cc
[modify] https://crrev.com/f4153114859e218c8fe5bef9293f2ec07d9bd276/ui/aura/env.h
[modify] https://crrev.com/f4153114859e218c8fe5bef9293f2ec07d9bd276/ui/aura/mus/window_tree_client.cc
[modify] https://crrev.com/f4153114859e218c8fe5bef9293f2ec07d9bd276/ui/aura/test/env_test_helper.h
[modify] https://crrev.com/f4153114859e218c8fe5bef9293f2ec07d9bd276/ui/views/mus/BUILD.gn
[add] https://crrev.com/f4153114859e218c8fe5bef9293f2ec07d9bd276/ui/views/mus/drag_interactive_uitest.cc
[modify] https://crrev.com/f4153114859e218c8fe5bef9293f2ec07d9bd276/ui/views/mus/interactive_ui_tests_manifest.json
[modify] https://crrev.com/f4153114859e218c8fe5bef9293f2ec07d9bd276/ui/views/mus/mus_client.cc
[modify] https://crrev.com/f4153114859e218c8fe5bef9293f2ec07d9bd276/ui/views/mus/mus_client.h
[modify] https://crrev.com/f4153114859e218c8fe5bef9293f2ec07d9bd276/ui/views/mus/test_utils.h