ozone/wayland: launch dbus for tests with Wayland

dbus_unittests failed in Ozone/Wayland tester as long as
dbus wasn't launched. The error message about missing
"$DISPLAY for X11" was misleading, and it was just rather
required to launch dbus via xvfb script.

This CL fixes the issue by reusing the existing method in the
same script that is able to launch Dbus for Wayland
as well (the "xvfb.py --use-weston --no-xvfb" case).

Bug: 1184129
Change-Id: Ie0580e280c10344c3795cf4ac46575bfe4a3dff6
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2739479
Auto-Submit: Maksim Sisov <msisov@igalia.com>
Commit-Queue: Dirk Pranke <dpranke@google.com>
Reviewed-by: Dirk Pranke <dpranke@google.com>
Cr-Commit-Position: refs/heads/master@{#860288}

dbus/BUILD.gn

@@ -102,8 +102,6 @@ test("dbus_unittests") {
   ]
 
   configs += [ "//build/config/linux/dbus" ]
-
-  data_deps = [ "//testing/buildbot/filters:dbus_unittests_filters" ]
 }
 
 executable("dbus_test_server") {

testing/buildbot/chromium.linux.json

@@ -6225,8 +6225,7 @@
           "--no-xvfb",
           "--use-weston",
           "--ozone-platform=wayland",
-          "--enable-features=UseOzonePlatform",
-          "--test-launcher-filter-file=../../testing/buildbot/filters/ozone-linux.dbus_unittests_wayland.filter"
+          "--enable-features=UseOzonePlatform"
         ],
         "merge": {
           "args": [],

testing/buildbot/filters/BUILD.gn

@@ -124,13 +124,6 @@ source_set("content_unittests_filters") {
   data = [ "//testing/buildbot/filters/webrtc.content_unittests.filter" ]
 }
 
-source_set("dbus_unittests_filters") {
-  testonly = true
-
-  data =
-      [ "//testing/buildbot/filters/ozone-linux.dbus_unittests_wayland.filter" ]
-}
-
 source_set("sync_integration_tests_filters") {
   testonly = true
 

testing/buildbot/test_suite_exceptions.pyl

@@ -1259,16 +1259,6 @@
       },
     },
   },
-  'dbus_unittests_wayland': {
-    'modifications': {
-      # CI Ozone/Wayland tester.
-      'Linux Tester (Ozone Wayland)': {
-        'args': [
-          '--test-launcher-filter-file=../../testing/buildbot/filters/ozone-linux.dbus_unittests_wayland.filter',
-        ],
-      },
-    }
-  },
   'depth_capture_tests': {
     # TODO(https://crbug.com/850107): Remove the Android FYI Release (Pixel 2)
     # exception once there is enough capacity to run these tests.

testing/xvfb.py

@@ -243,6 +243,8 @@ def _run_with_weston(cmd, env, stdoutfile):
     signal.signal(signal.SIGTERM, raise_weston_error)
     signal.signal(signal.SIGINT, raise_weston_error)
 
+    dbus_pid = launch_dbus(env)
+
     # The bundled weston (//third_party/weston) is used by Linux Ozone Wayland
     # CI and CQ testers and compiled by //ui/ozone/platform/wayland whenever
     # there is a dependency on the Ozone/Wayland and use_bundled_weston is set
@@ -302,6 +304,11 @@ def _run_with_weston(cmd, env, stdoutfile):
   finally:
     kill(weston_proc, 'weston')
 
+    # dbus-daemon is not a subprocess, so we can't SIGTERM+waitpid() on it.
+    # To ensure it exits, use SIGKILL which should be safe since all other
+    # processes that it would have been servicing have exited.
+    if dbus_pid:
+      os.kill(dbus_pid, signal.SIGKILL)
 
 def _get_display_from_weston(weston_proc_pid):
   """Retrieves $WAYLAND_DISPLAY set by Weston.