net: Implement ChannelIDSourceChromium, which is based on Chromium's

net/quic/test_tools/crypto_test_utils.h

Index: net/quic/test_tools/crypto_test_utils.h
===================================================================
--- net/quic/test_tools/crypto_test_utils.h	(revision 280648)
+++ net/quic/test_tools/crypto_test_utils.h	(working copy)
@@ -100,6 +100,15 @@
   // returned by |ProofVerifierForTesting|.
   static ProofVerifyContext* ProofVerifyContextForTesting();
 
+  // These functions return a fake |ProofSource|, |ProofVerifier|, or
+  // |ProofVerifyContext| that works with each other. These are suitable for
+  // unit tests that aren't concerned with |ProofSource| and |ProofVerifier|.
+  // TODO(wtc): delete these when Chromium has a working
+  // ProofSourceForTesting().
+  static ProofSource* FakeProofSourceForTesting();
+  static ProofVerifier* FakeProofVerifierForTesting();
+  static ProofVerifyContext* FakeProofVerifyContextForTesting();
+
   // MockCommonCertSets returns a CommonCertSets that contains a single set with
   // hash |hash|, consisting of the certificate |cert| at index |index|.
   static CommonCertSets* MockCommonCertSets(base::StringPiece cert,