chromeos: Remove AshTestBase::SupportsMultipleDisplays

ash/display/screen_ash_unittest.cc

Index: ash/display/screen_ash_unittest.cc
diff --git a/ash/display/screen_ash_unittest.cc b/ash/display/screen_ash_unittest.cc
index 747474f6878b7c205835bc29e34e27c0bf0625d2..4f02ab0f1c5783cde571364ddfdda45f5e2bbc6a 100644
--- a/ash/display/screen_ash_unittest.cc
+++ b/ash/display/screen_ash_unittest.cc
@@ -22,9 +22,6 @@ class ScreenAshTest : public test::AshTestBase {
 // Tests that ScreenAsh::GetWindowAtScreenPoint() returns the correct window on
 // the correct display.
 TEST_F(ScreenAshTest, TestGetWindowAtScreenPoint) {
-  if (!SupportsMultipleDisplays())
-    return;
-
   UpdateDisplay("200x200,400x400");
 
   aura::test::TestWindowDelegate delegate;