chromeos: Remove AshTestBase::SupportsMultipleDisplays

ash/system/overview/overview_button_tray_unittest.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ash/common/system/overview/overview_button_tray.h"
 
 #include "ash/common/login_status.h"
 #include "ash/common/system/status_area_widget.h"
 #include "ash/common/test/test_session_state_delegate.h"
 #include "ash/common/wm/maximize_mode/maximize_mode_controller.h"
@@ skipping 123 matching lines @@
   // user action.
   GetTray()->PerformAction(tap);
   ASSERT_FALSE(WmShell::Get()->window_selector_controller()->IsSelecting());
   EXPECT_EQ(3, user_action_tester.GetActionCount(kTrayOverview));
 }
 
 // Tests that a second OverviewButtonTray has been created, and only shows
 // when MaximizeMode has been enabled,  when we are using multiple displays.
 // By default the DisplayManger is in extended mode.
 TEST_F(OverviewButtonTrayTest, DisplaysOnBothDisplays) {
-  if (!SupportsMultipleDisplays())
-    return;
-
   UpdateDisplay("400x400,200x200");
   EXPECT_FALSE(GetTray()->visible());
   EXPECT_FALSE(GetSecondaryTray()->visible());
   WmShell::Get()->maximize_mode_controller()->EnableMaximizeModeWindowManager(
       true);
   EXPECT_TRUE(GetTray()->visible());
   EXPECT_TRUE(GetSecondaryTray()->visible());
   WmShell::Get()->maximize_mode_controller()->EnableMaximizeModeWindowManager(
       false);
 }
 
 // Tests if Maximize Mode is enabled before a secondary display is attached
 // that the second OverviewButtonTray should be created in a visible state.
 TEST_F(OverviewButtonTrayTest, SecondaryTrayCreatedVisible) {
-  if (!SupportsMultipleDisplays())
-    return;
-
   WmShell::Get()->maximize_mode_controller()->EnableMaximizeModeWindowManager(
       true);
   UpdateDisplay("400x400,200x200");
   EXPECT_TRUE(GetSecondaryTray()->visible());
   WmShell::Get()->maximize_mode_controller()->EnableMaximizeModeWindowManager(
       false);
 }
 
 // Tests that the tray loses visibility when a user logs out, and that it
 // regains visibility when a user logs back in.
@@ skipping 77 matching lines @@
   ASSERT_TRUE(WmShell::Get()->IsSystemModalWindowOpen());
   WmShell::Get()->maximize_mode_controller()->EnableMaximizeModeWindowManager(
       true);
   EXPECT_TRUE(GetTray()->visible());
   WmShell::Get()->maximize_mode_controller()->EnableMaximizeModeWindowManager(
       false);
   EXPECT_FALSE(GetTray()->visible());
 }
 
 }  // namespace ash