Forces use mesa switch in mash_unittests and views_aura_mus_unittests

ui/views/mus/views_aura_mus_test_suite.cc

Index: ui/views/mus/views_aura_mus_test_suite.cc
diff --git a/ui/views/mus/views_aura_mus_test_suite.cc b/ui/views/mus/views_aura_mus_test_suite.cc
index 19fc23864976b6748638ac7ddcf4e685da0d3435..0c3f0bd5dd9befc7814f7fb2b16d0a870fb3e27e 100644
--- a/ui/views/mus/views_aura_mus_test_suite.cc
+++ b/ui/views/mus/views_aura_mus_test_suite.cc
@@ -22,6 +22,7 @@
 #include "ui/aura/mus/window_tree_host_mus.h"
 #include "ui/aura/test/env_test_helper.h"
 #include "ui/aura/window.h"
+#include "ui/gl/gl_switches.h"
 #include "ui/views/mus/desktop_window_tree_host_mus.h"
 #include "ui/views/mus/mus_client.h"
 #include "ui/views/mus/test_utils.h"
@@ -199,6 +200,8 @@ void ViewsAuraMusTestSuite::Initialize() {
   // setup for tests (e.g. to unlock the screen in the window manager).
   EnsureCommandLineSwitch(ui::switches::kUseTestConfig);
 
+  EnsureCommandLineSwitch(switches::kOverrideUseGLWithOSMesaForTests);
+
   ViewsTestSuite::Initialize();
   service_manager_connections_ = base::MakeUnique<ServiceManagerConnection>();
 }