* Auditing Ozone usage in //content
*** //content/browser/compositor/gpu_process_transport_factory.cc
***** Only creator of //content/browser/compositor/software_output_device_ozone.cc
******* Not a problem since this is guarded by a check to aura::Env::mode().
***** In case of --enable-hardware-overlays, will use ozone's OverlayManager.
*** //content/browser/compositor/software_output_device_ozone.cc
***** Only used in GpuProcessTransportFactory above.
*** //content/browser/gpu/gpu_data_manager_impl_private.cc
***** Only uses ozone switches.
*** //content/browser/gpu/gpu_process_host.cc
***** Glue code that delivers IPC::Message s to Ozone.
***** May be unused in mojo land? I couldn't get them called in --mus.
*** //content/browser/renderer_host/render_process_host_impl.cc
***** Only uses ozone switches.
*** //content/common/cursors/webcursor_ozone.cc
***** Deeply intertwined with CursorFactoryOzone.
***** Previous work was done to make this work in --mus and --mash.
*** //content/gpu/gpu_child_thread.cc
***** GPUChildThread doesn't appear to be instantiated in --mus builds.
***** (But it is instantiated in classic ash.)
*** //content/gpu/gpu_main.cc
***** Doesn't get executed in --mus.
***** (It's just used to create a base::MessageLoop, anyway.)
*** //content/renderer/renderer_main.cc
***** This is in the renderer, but it then shells out to ozone.
***** I think this is safe?
***** This is done in the renderer which already doesn't have access to ozone.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/2f18c48d9bc872338fa02eda3778461b4f091139

commit 2f18c48d9bc872338fa02eda3778461b4f091139
Author: Elliot Glaysher <erg@chromium.org>
Date: Thu Aug 17 18:18:44 2017

Constrict DEPS so //content/ can't add further dependencies on ozone.

Under --mus and --mash, the code in //content/ can't access the raw
ozone devices. It appears the most of the uses of ozone aren't used in
mus builds anyway. Further constrain DEPS so new instances can't be
added.

Bug:  734668 
Change-Id: I5b8661aa4c000a58602ffce0e6f3e9cf35cff87e
Reviewed-on: https://chromium-review.googlesource.com/617591
Reviewed-by: Scott Violet <sky@chromium.org>
Commit-Queue: Elliot Glaysher <erg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#495228}
[modify] https://crrev.com/2f18c48d9bc872338fa02eda3778461b4f091139/content/DEPS
[modify] https://crrev.com/2f18c48d9bc872338fa02eda3778461b4f091139/content/browser/compositor/DEPS
[add] https://crrev.com/2f18c48d9bc872338fa02eda3778461b4f091139/content/browser/gpu/DEPS
[modify] https://crrev.com/2f18c48d9bc872338fa02eda3778461b4f091139/content/browser/renderer_host/DEPS
[modify] https://crrev.com/2f18c48d9bc872338fa02eda3778461b4f091139/content/common/cursors/DEPS
[modify] https://crrev.com/2f18c48d9bc872338fa02eda3778461b4f091139/content/gpu/DEPS
[modify] https://crrev.com/2f18c48d9bc872338fa02eda3778461b4f091139/content/public/test/content_test_suite_base.cc
[modify] https://crrev.com/2f18c48d9bc872338fa02eda3778461b4f091139/content/renderer/DEPS

The only potentially unwanted use of ozone in content which occurs in --mus is in RenderMain:

  g_pixmap_factory.Get() = ui::CreateClientNativePixmapFactoryOzone();

This should be OK, in as much as we already build one of these objects not just in the renderer, but in every aura using process, but I'm not 100% sure of this.

Given the comments in https://codereview.chromium.org/2803523002, I'm going to say that that final usage is ok.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/891067b2c40e0624546cb9d8ee5c9777b9760a3b

commit 891067b2c40e0624546cb9d8ee5c9777b9760a3b
Author: Evan Stade <estade@chromium.org>
Date: Fri Nov 16 01:26:33 2018

Don't use ui::CursorData as PlatformCursor for mash clients.

ui::Cursor now holds the data necessary for custom cursors, although for
simplicity this patch still converts to CursorData for serializing over
mojo.

CursorFactoryOzone goes back to being a true singleton, which shouldn't
be used from client code in Mash (in Oop Mash, it's actually null; in
single process Mash it is avoided by checking the feature switch).

This patch also makes some tweaks to how custom web cursors are stored
as ui::Cursors, which shouldn't impact other platforms but brings the
ui::Cursor representation into alignment with the PlatformCursor
representation for ozone.

As a future cleanup we should be able to get rid of CursorData and
serialize ui::Cursor directly.

Bug:  904039 ,  734668 
Change-Id: I4168c0266899bd276c60a0ac6a286b3a79df572f
Reviewed-on: https://chromium-review.googlesource.com/c/1334968
Commit-Queue: Evan Stade <estade@chromium.org>
Reviewed-by: Scott Violet <sky@chromium.org>
Reviewed-by: Bret Sepulveda <bsep@chromium.org>
Reviewed-by: Michael Spang <spang@chromium.org>
Cr-Commit-Position: refs/heads/master@{#608617}
[modify] https://crrev.com/891067b2c40e0624546cb9d8ee5c9777b9760a3b/ash/components/tap_visualizer/tap_visualizer_app_unittest.cc
[modify] https://crrev.com/891067b2c40e0624546cb9d8ee5c9777b9760a3b/ash/ws/ash_window_manager_unittest.cc
[modify] https://crrev.com/891067b2c40e0624546cb9d8ee5c9777b9760a3b/chrome/browser/ui/ash/chrome_browser_main_extra_parts_ash.cc
[modify] https://crrev.com/891067b2c40e0624546cb9d8ee5c9777b9760a3b/content/common/cursors/webcursor.h
[modify] https://crrev.com/891067b2c40e0624546cb9d8ee5c9777b9760a3b/content/common/cursors/webcursor_aura.cc
[modify] https://crrev.com/891067b2c40e0624546cb9d8ee5c9777b9760a3b/content/common/cursors/webcursor_aurawin.cc
[modify] https://crrev.com/891067b2c40e0624546cb9d8ee5c9777b9760a3b/content/common/cursors/webcursor_aurax11.cc
[modify] https://crrev.com/891067b2c40e0624546cb9d8ee5c9777b9760a3b/content/common/cursors/webcursor_ozone.cc
[modify] https://crrev.com/891067b2c40e0624546cb9d8ee5c9777b9760a3b/content/common/cursors/webcursor_unittest.cc
[modify] https://crrev.com/891067b2c40e0624546cb9d8ee5c9777b9760a3b/ui/base/BUILD.gn
[delete] https://crrev.com/7de3a17b0ef130a5723f012829bb9170139394e8/ui/base/cursor/ozone/cursor_data_factory_ozone.cc
[delete] https://crrev.com/7de3a17b0ef130a5723f012829bb9170139394e8/ui/base/cursor/ozone/cursor_data_factory_ozone.h
[modify] https://crrev.com/891067b2c40e0624546cb9d8ee5c9777b9760a3b/ui/ozone/public/cursor_factory_ozone.cc
[modify] https://crrev.com/891067b2c40e0624546cb9d8ee5c9777b9760a3b/ui/views/mus/desktop_window_tree_host_mus.cc
[modify] https://crrev.com/891067b2c40e0624546cb9d8ee5c9777b9760a3b/ui/views/mus/mus_client.cc
[modify] https://crrev.com/891067b2c40e0624546cb9d8ee5c9777b9760a3b/ui/views/mus/mus_client.h