Revert of Add a presubmit check that warns about declaring Singleton<T> in header files

PRESUBMIT_test.py

Index: PRESUBMIT_test.py
diff --git a/PRESUBMIT_test.py b/PRESUBMIT_test.py
index 7de0c3b61f5da2e8ec7d46c2f532477223a6d3ef..00997b43e8a170ecb8b3e1f30b1a14051424d013 100755
--- a/PRESUBMIT_test.py
+++ b/PRESUBMIT_test.py
@@ -382,33 +382,6 @@
     ])
     results = PRESUBMIT.GetPreferredTryMasters(None, mock_change)
     self.assertEqual({}, results)
-
-
-class CheckSingletonInHeadersTest(unittest.TestCase):
-  def testSingletonInArbitraryHeader(self):
-    diff_singleton_h = ['base::subtle::AtomicWord '
-                        'Singleton<Type, Traits, DifferentiatingType>::']
-    diff_foo_h = ['// Singleton<Foo> in comment.',
-                  'friend class Singleton<Foo>']
-    diff_bad_h = ['Foo* foo = Singleton<Foo>::get();']
-    mock_input_api = MockInputApi()
-    mock_input_api.files = [MockFile('base/memory/singleton.h',
-                                     diff_singleton_h),
-                            MockFile('foo.h', diff_foo_h),
-                            MockFile('bad.h', diff_bad_h)]
-    warnings = PRESUBMIT._CheckSingletonInHeaders(mock_input_api,
-                                                  MockOutputApi())
-    self.assertEqual(1, len(warnings))
-    self.assertEqual('error', warnings[0].type)
-    self.assertTrue('Found Singleton<T>' in warnings[0].message)
-
-  def testSingletonInCC(self):
-    diff_cc = ['Foo* foo = Singleton<Foo>::get();']
-    mock_input_api = MockInputApi()
-    mock_input_api.files = [MockFile('some/path/foo.cc', diff_cc)]
-    warnings = PRESUBMIT._CheckSingletonInHeaders(mock_input_api,
-                                                  MockOutputApi())
-    self.assertEqual(0, len(warnings))
 
 
 class InvalidOSMacroNamesTest(unittest.TestCase):