Libchrome unit testing is not set up, but since we use Chromium's versions of preg_parser and registry_dict now, we don't really need unit tests, anyway.

Still consider adding a fuzzer.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/479c5684bd7b22ab6305c20ae7266506f39149f5

commit 479c5684bd7b22ab6305c20ae7266506f39149f5
Author: ljusten <ljusten@chromium.org>
Date: Tue Apr 18 08:50:20 2017

Add fuzzer test for preg_parser

The fuzzer does not hook into ReadFile since that reads files and
uses PolicyLoadStatusSample, which in turn creates a histogram entry.
This leads to OOM quicky since the samples accumulate. Thus, this CL
adds a new equivalent ReadData that reads data from memory and writes
status to an PolicyLoadStatus enum.

BUG= 660007 
TEST=Compiled, ran unit tests and fuzzer

Review-Url: https://codereview.chromium.org/2791193005
Cr-Commit-Position: refs/heads/master@{#465179}

[add] https://crrev.com/479c5684bd7b22ab6305c20ae7266506f39149f5/chrome/test/data/policy/gpo/fuzzer.dict
[add] https://crrev.com/479c5684bd7b22ab6305c20ae7266506f39149f5/chrome/test/data/policy/gpo/fuzzer_corpus/empty.pol
[add] https://crrev.com/479c5684bd7b22ab6305c20ae7266506f39149f5/chrome/test/data/policy/gpo/fuzzer_corpus/extension_alternative_spelling.pol
[add] https://crrev.com/479c5684bd7b22ab6305c20ae7266506f39149f5/chrome/test/data/policy/gpo/fuzzer_corpus/registry.pol
[add] https://crrev.com/479c5684bd7b22ab6305c20ae7266506f39149f5/chrome/test/data/policy/gpo/fuzzer_corpus/test1.pol
[add] https://crrev.com/479c5684bd7b22ab6305c20ae7266506f39149f5/chrome/test/data/policy/gpo/fuzzer_corpus/test2.pol
[add] https://crrev.com/479c5684bd7b22ab6305c20ae7266506f39149f5/chrome/test/data/policy/gpo/fuzzer_corpus/test3.pol
[add] https://crrev.com/479c5684bd7b22ab6305c20ae7266506f39149f5/chrome/test/data/policy/gpo/fuzzer_corpus/test4.pol
[add] https://crrev.com/479c5684bd7b22ab6305c20ae7266506f39149f5/chrome/test/data/policy/gpo/fuzzer_corpus/test5.pol
[add] https://crrev.com/479c5684bd7b22ab6305c20ae7266506f39149f5/chrome/test/data/policy/gpo/fuzzer_corpus/test6.pol
[modify] https://crrev.com/479c5684bd7b22ab6305c20ae7266506f39149f5/components/policy/core/common/BUILD.gn
[modify] https://crrev.com/479c5684bd7b22ab6305c20ae7266506f39149f5/components/policy/core/common/preg_parser.cc
[modify] https://crrev.com/479c5684bd7b22ab6305c20ae7266506f39149f5/components/policy/core/common/preg_parser.h
[add] https://crrev.com/479c5684bd7b22ab6305c20ae7266506f39149f5/components/policy/core/common/preg_parser_fuzzer.cc

bulk Verify of Chromad V1 bugs