Reland: cros: Eliminate the ash::test namespace

Reland of https://chromium-review.googlesource.com/c/573324 after
one-line compile fix.

We are inconsistent in our usage of this namespace. We mostly use it
for test support code, but not always. We sometimes wrap tests in it,
but not always.

After discussion with top-level ash OWNERS we're going to eliminate
the namespace entirely. This is more consistent with unittest.cc
files in the rest of Chrome.

[email protected]
[email protected]

Bug: none
Test: compiles, ash_unittests, chrome unit_tests
Change-Id: I6afce9fb02614469e36a20cc1b0f53b1ddca551d
Reviewed-on: https://chromium-review.googlesource.com/575766
Reviewed-by: James Cook <[email protected]>
Reviewed-by: Dan Erat <[email protected]>
Commit-Queue: James Cook <[email protected]>
Cr-Commit-Position: refs/heads/master@{#487344}
diff --git a/ash/window_user_data_unittest.cc b/ash/window_user_data_unittest.cc
index d4d2de2..39a2def1 100644
--- a/ash/window_user_data_unittest.cc
+++ b/ash/window_user_data_unittest.cc
@@ -30,7 +30,7 @@
 
 }  // namespace
 
-using WindowUserDataTest = test::AshTestBase;
+using WindowUserDataTest = AshTestBase;
 
 // Verifies clear() deletes the data associated with a window.
 TEST_F(WindowUserDataTest, ClearDestroys) {