Add initial support for compiler unit tests using GTest/GMock.

tools/presubmit.py

 #!/usr/bin/env python
 #
 # Copyright 2012 the V8 project authors. All rights reserved.
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are
 # met:
 #
 #     * Redistributions of source code must retain the above copyright
 #       notice, this list of conditions and the following disclaimer.
 #     * Redistributions in binary form must reproduce the above
@@ skipping 219 matching lines @@
 
   IGNORE_LINT = ['flag-definitions.h']
 
   def IgnoreFile(self, name):
     return (super(CppLintProcessor, self).IgnoreFile(name)
               or (name in CppLintProcessor.IGNORE_LINT))
 
   def GetPathsToSearch(self):
     return ['src', 'include', 'samples',
             join('test', 'base-unittests'),
-            join('test', 'cctest')]
+            join('test', 'cctest'),
+            join('test', 'compiler-unittests')]
 
   def GetCpplintScript(self, prio_path):
     for path in [prio_path] + os.environ["PATH"].split(os.pathsep):
       path = path.strip('"')
       cpplint = os.path.join(path, "cpplint.py")
       if os.path.isfile(cpplint):
         return cpplint
 
     return None
 
@@ skipping 201 matching lines @@
   success = CheckGeneratedRuntimeTests(workspace) and success
   success = CheckExternalReferenceRegistration(workspace) and success
   if success:
     return 0
   else:
     return 1
 
 
 if __name__ == '__main__':
   sys.exit(Main())