Presubmit: Skip third_party for fwd decl warning

Skip presubmit warning when the introduced useless forward
declaration is made in third_party (with the exception of
blink). Take the opportunity to fix one test and style.

BUG=662195
TEST=PRESUBMIT_test.py ForwardDeclarationTest

Review-Url: https://codereview.chromium.org/2568473002
Cr-Commit-Position: refs/heads/master@{#437833}

PRESUBMIT.py

@@ -1586,8 +1586,9 @@ def _CheckMojoUsesNewWrapperTypes(input_api, output_api):
 
 
 def _CheckUselessForwardDeclarations(input_api, output_api):
-  """Checks that added or removed lines in affected header files
-     do not lead to new useless class or struct forward declaration.
+  """Checks that added or removed lines in non third party affected
+     header files do not lead to new useless class or struct forward
+     declaration.
   """
   results = []
   class_pattern = input_api.re.compile(r'^class\s+(\w+);$',
@@ -1595,6 +1596,11 @@ def _CheckUselessForwardDeclarations(input_api, output_api):
   struct_pattern = input_api.re.compile(r'^struct\s+(\w+);$',
                                         input_api.re.MULTILINE)
   for f in input_api.AffectedFiles(include_deletes=False):
+    if (f.LocalPath().startswith('third_party') and
+        not f.LocalPath().startswith('third_party/WebKit') and
+        not f.LocalPath().startswith('third_party\\WebKit')):
+      continue
+
     if not f.LocalPath().endswith('.h'):
       continue
 

PRESUBMIT_test.py

@@ -1115,11 +1115,14 @@ class HardcodedGoogleHostsTest(unittest.TestCase):
 
 
 class ForwardDeclarationTest(unittest.TestCase):
-  def testCheckHeadersOnly(self):
+  def testCheckHeadersOnlyOutsideThirdParty(self):
     mock_input_api = MockInputApi()
     mock_input_api.files = [
       MockAffectedFile('somewhere/file.cc', [
         'class DummyClass;'
+      ]),
+      MockAffectedFile('third_party/header.h', [
+        'class DummyClass;'
       ])
     ]
     warnings = PRESUBMIT._CheckUselessForwardDeclarations(mock_input_api,
@@ -1130,9 +1133,9 @@ class ForwardDeclarationTest(unittest.TestCase):
     mock_input_api = MockInputApi()
     mock_input_api.files = [
       MockAffectedFile('somewhere/header.h', [
-        'class SomeClass {'
-        ' protected:'
-        '  class NotAMatch;'
+        'class SomeClass {',
+        ' protected:',
+        '  class NotAMatch;',
         '};'
       ])
     ]
@@ -1162,12 +1165,28 @@ class ForwardDeclarationTest(unittest.TestCase):
         'struct DummyStruct;',
         'class UsefulClass;',
         'std::unique_ptr<UsefulClass> p;'
-      ]),
+      ])
     ]
     warnings = PRESUBMIT._CheckUselessForwardDeclarations(mock_input_api,
       MockOutputApi())
     self.assertEqual(2, len(warnings))
 
+  def testBlinkHeaders(self):
+    mock_input_api = MockInputApi()
+    mock_input_api.files = [
+      MockAffectedFile('third_party/WebKit/header.h', [
+        'class DummyClass;',
+        'struct DummyStruct;',
+      ]),
+      MockAffectedFile('third_party\\WebKit\\header.h', [
+        'class DummyClass;',
+        'struct DummyStruct;',
+      ])
+    ]
+    warnings = PRESUBMIT._CheckUselessForwardDeclarations(mock_input_api,
+      MockOutputApi())
+    self.assertEqual(4, len(warnings))
+
 
 if __name__ == '__main__':
   unittest.main()

PRESUBMIT_test_mocks.py

@@ -120,7 +120,7 @@ class MockFile(object):
     return self._local_path
 
   def GenerateScmDiff(self):
-    return self._scm_diff;
+    return self._scm_diff
 
   def rfind(self, p):
     """os.path.basename is called on MockFile so we need an rfind method."""