It looks like there might have been some churn with widget dimensions requiring test expectations to be revisited.

[ RUN      ] ImmersiveModeControllerAshHostedAppBrowserTest.Layout
[27221:27221:0412/105125.924842:WARNING:user_policy_manager_factory_chromeos.cc(194)] No policy loaded for known non-enterprise user
[27221:27221:0412/105125.976928:WARNING:user_session_manager.cc(1082)] Attempting to save user password for non enterprise user.
[27221:27221:0412/105126.403364:ERROR:network_type_pattern.cc(134)] NetworkTypePattern: wifi: Can not match empty type.
[27221:27221:0412/105126.404851:ERROR:network_type_pattern.cc(134)] NetworkTypePattern: wifi: Can not match empty type.
[27221:27221:0412/105126.407447:ERROR:network_type_pattern.cc(134)] NetworkTypePattern: wifi: Can not match empty type.
[27221:27221:0412/105126.407948:ERROR:network_type_pattern.cc(134)] NetworkTypePattern: wifi: Can not match empty type.
[27221:27235:0412/105127.210237:WARNING:simple_synchronous_entry.cc(1255)] Could not open platform files for entry.
../../chrome/browser/ui/views/frame/immersive_mode_controller_ash_browsertest.cc:149: Failure
Expected equality of these values:
  header_height
    Which is: 33
  GetBoundsInWidget(contents_web_view).y()
    Which is: 54
[27221:27246:0412/105128.230635:WARNING:discardable_shared_memory_manager.cc(436)] Some MojoDiscardableSharedMemoryManagerImpls are still alive. They will be leaked.
[27221:27221:0412/105128.344718:WARNING:url_request_context_getter.cc(43)] URLRequestContextGetter leaking due to no owning thread.
[27221:27221:0412/105128.425937:WARNING:pref_notifier_impl.cc(23)] Pref observer found at shutdown.
[27221:27221:0412/105128.426033:WARNING:pref_notifier_impl.cc(23)] Pref observer found at shutdown.
[  FAILED  ] ImmersiveModeControllerAshHostedAppBrowserTest.Layout, where TypeParam =  and GetParam() =  (3335 ms)

Reassigning to mgiuca@chromium.org because erg@'s last visit was >30d ago

Hmm, erg@ has indeed left, but I'm not sure how I got chosen (I have nothing to do with immersive_mode_controller_ash).

Note: This is Chrome OS, not Linux.

Assigning to oshima@ who most recently touched the code-under-test (immersive_mode_controller_ash.cc); in fact this could be the culprit CL: r550035. Also CC sammiequon@ who recently touched this file and the test.