Presubmit: Warn about useless forward declarations

PRESUBMIT_test_mocks.py

Index: PRESUBMIT_test_mocks.py
diff --git a/PRESUBMIT_test_mocks.py b/PRESUBMIT_test_mocks.py
index 772f405725be0f575c193ad0ecac46d93d973d06..37b0159276df974fcb9cef44f39fdd4473913273 100644
--- a/PRESUBMIT_test_mocks.py
+++ b/PRESUBMIT_test_mocks.py
@@ -99,6 +99,10 @@ class MockFile(object):
     self._new_contents = new_contents
     self._changed_contents = [(i + 1, l) for i, l in enumerate(new_contents)]
     self._action = action
+    self._scm_diff = "--- /dev/null\n+++ %s\n@@ -0,0 +1,%d @@\n" % (local_path,
+      len(new_contents))
+    for l in new_contents:
+      self._scm_diff += "+%s\n" % l
 
   def Action(self):
     return self._action
@@ -115,6 +119,9 @@ class MockFile(object):
   def AbsoluteLocalPath(self):
     return self._local_path
 
+  def GenerateScmDiff(self):
+    return self._scm_diff;
+
   def rfind(self, p):
     """os.path.basename is called on MockFile so we need an rfind method."""
     return self._local_path.rfind(p)