chromeos: Remove AshTestBase::SupportsMultipleDisplays

ash/test/ash_test_helper.h

Index: ash/test/ash_test_helper.h
diff --git a/ash/test/ash_test_helper.h b/ash/test/ash_test_helper.h
index 73086777eacc0d3048534be9a4972d95a48916da..eb6657ce2db4e924c81ad7bbc3876bb737a9b447 100644
--- a/ash/test/ash_test_helper.h
+++ b/ash/test/ash_test_helper.h
@@ -70,10 +70,6 @@ class AshTestHelper {
 
   AshTestEnvironment* ash_test_environment() { return ash_test_environment_; }
 
-  // True if the running environment supports multiple displays,
-  // or false otherwise (e.g. win8 bot).
-  static bool SupportsMultipleDisplays();
-
  private:
   AshTestEnvironment* ash_test_environment_;  // Not owned.
   TestShellDelegate* test_shell_delegate_;  // Owned by ash::Shell.