Revert of Add a presubmit check that warns about declaring Singleton<T> in header files (patchset #2 id:20001 of https://codereview.chromium.org/929043002/)

Reason for revert:
Reverting because of presubmit crashes:

Traceback (most recent call last):
  File "/usr/local/google/ssd/depot_tools/git_cl.py", line 2983, in <module>
    sys.exit(main(sys.argv[1:]))
  File "/usr/local/google/ssd/depot_tools/git_cl.py", line 2969, in main
    return dispatcher.execute(OptionParser(), argv)
  File "/usr/local/google/ssd/depot_tools/subcommand.py", line 245, in execute
    return command(parser, args[1:])
  File "/usr/local/google/ssd/depot_tools/git_cl.py", line 1614, in CMDpresubmit
    change=cl.GetChange(base_branch, None))
  File "/usr/local/google/ssd/depot_tools/git_cl.py", line 936, in RunHook
    rietveld_obj=self.RpcServer())
  File "/usr/local/google/ssd/depot_tools/presubmit_support.py", line 1396, in DoPresubmitChecks
    results += executer.ExecPresubmitScript(presubmit_script, filename)
  File "/usr/local/google/ssd/depot_tools/presubmit_support.py", line 1313, in ExecPresubmitScript
    result = eval(function_name + '(*__args)', context)
  File "<string>", line 1, in <module>
  File "<string>", line 1727, in CheckChangeOnCommit
  File "<string>", line 1455, in _CommonChecks
  File "<string>", line 1322, in _CheckSingletonInHeaders
  File "/usr/local/google/ssd/depot_tools/presubmit_support.py", line 472, in ReadFile
    raise IOError('Access outside the repository root is denied.')
IOError: Access outside the repository root is denied.

Original issue's description:
> Add a presubmit check that warns about declaring Singleton<T> in header files
> (except for base/memory/singleton.h)
> This check is copied from presubmit_canned_checks.py in depot_tools/ with an
> added exception for base/memory/singleton.h.
> The corresponding code will be removed from presubmit_canned_checks.py afterwards.
>
> BUG=349861
> R=phajdan.jr@chromium.org,
>
> Committed: https://crrev.com/9b73d0393037452d13358f4e2766cb62adbdede8
> Cr-Commit-Position: refs/heads/master@{#316546}

TBR=phajdan.jr@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=349861

Review URL: https://codereview.chromium.org/934723003

Cr-Commit-Position: refs/heads/master@{#316559}

3 files changed, 0 insertions, 61 deletions

diff --git a/PRESUBMIT.py b/PRESUBMIT.py
index 3000e10..18fe621 100644
--- a/PRESUBMIT.py
+++ b/PRESUBMIT.py
@@ -1305,36 +1305,6 @@ def _CheckForCopyrightedCode(input_api, output_api):
   return copyright_scanner.ScanAtPresubmit(input_api, output_api)
 
 
-def _CheckSingletonInHeaders(input_api, output_api):
-  """Checks to make sure no header files have |Singleton<|."""
-  def FileFilter(affected_file):
-    # It's ok for base/memory/singleton.h to have |Singleton<|.
-    black_list = (_EXCLUDED_PATHS +
-                  input_api.DEFAULT_BLACK_LIST +
-                  (r"^base[\\\/]memory[\\\/]singleton\.h$",))
-    return input_api.FilterSourceFile(affected_file, black_list=black_list)
-
-  pattern = input_api.re.compile(r'(?<!class\s)Singleton\s*<')
-  files = []
-  for f in input_api.AffectedSourceFiles(FileFilter):
-    if (f.LocalPath().endswith('.h') or f.LocalPath().endswith('.hxx') or
-        f.LocalPath().endswith('.hpp') or f.LocalPath().endswith('.inl')):
-      contents = input_api.ReadFile(f.LocalPath())
-      for line in contents.splitlines(False):
-        if (not input_api.re.match(r'//', line) and # Strip C++ comment.
-            pattern.search(line)):
-          files.append(f)
-          break
-
-  if files:
-    return [ output_api.PresubmitError(
-        'Found Singleton<T> in the following header files.\n' +
-        'Please move them to an appropriate source file so that the ' +
-        'template gets instantiated in a single compilation unit.',
-        files) ]
-  return []
-
-
 _DEPRECATED_CSS = [
   # Values
   ( "-webkit-box", "flex" ),
@@ -1452,7 +1422,6 @@ def _CommonChecks(input_api, output_api):
   results.extend(_CheckForIPCRules(input_api, output_api))
   results.extend(_CheckForCopyrightedCode(input_api, output_api))
   results.extend(_CheckForWindowsLineEndings(input_api, output_api))
-  results.extend(_CheckSingletonInHeaders(input_api, output_api))
 
   if any('PRESUBMIT.py' == f.LocalPath() for f in input_api.AffectedFiles()):
     results.extend(input_api.canned_checks.RunUnitTestsInDirectory(
diff --git a/PRESUBMIT_test.py b/PRESUBMIT_test.py
index 7de0c3b..00997b4 100755
--- a/PRESUBMIT_test.py
+++ b/PRESUBMIT_test.py
@@ -384,33 +384,6 @@ class BadExtensionsTest(unittest.TestCase):
     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):
   def testInvalidOSMacroNames(self):
     lines = ['#if defined(OS_WINDOWS)',
diff --git a/PRESUBMIT_test_mocks.py b/PRESUBMIT_test_mocks.py
index fa4f4bf..7d286b9 100644
--- a/PRESUBMIT_test_mocks.py
+++ b/PRESUBMIT_test_mocks.py
@@ -29,9 +29,6 @@ class MockInputApi(object):
   def AffectedFiles(self, file_filter=None):
     return self.files
 
-  def AffectedSourceFiles(self, file_filter=None):
-    return self.files
-
   def PresubmitLocalPath(self):
     return os.path.dirname(__file__)