Add a hook to inject trusted Cast roots for testing purposes.

extensions/common/cast/cast_cert_validator.h

Index: extensions/common/cast/cast_cert_validator.h
diff --git a/extensions/common/cast/cast_cert_validator.h b/extensions/common/cast/cast_cert_validator.h
index c435ebb8776f312edfb7c6bee440f028175c6d4f..2b0efb936b482f00750d615ce9c9e0aa5f11f4d7 100644
--- a/extensions/common/cast/cast_cert_validator.h
+++ b/extensions/common/cast/cast_cert_validator.h
@@ -86,6 +86,13 @@ bool VerifyDeviceCert(const std::vector<std::string>& certs,
 scoped_ptr<CertVerificationContext> CertVerificationContextImplForTest(
     const base::StringPiece& spki);
 
+// Exposed only for testing, not for use in production code.
+//
+// Injects trusted root certificates into the CastTrustStore.
+// Warning: Using this function concurrently with VerifyDeviceCert()
+//          is not thread safe.
+bool AddTrustAnchorForTest(const uint8_t* data,

[eroman, 2016/04/22 05:58:54]

Andrei suggested the name "AddDevTrustAnchorsForTest()" over email, what do you
think about that?

Assuming the dev trust anchors are fixed, this could internalize the certificate
data into the implementation rather than exposing a fully generic interface.

I am fine with either approach, so will defer to you/sheretov.

(My only concern with internalizing the data is ensuring the compilation is
smart enough to strip the unused data.)

[ryanchung, 2016/04/22 19:03:49]

We've decided to not bundle the test anchors for now. Also, Cast can ensure that
the test root is not compiled into production code.

+                           size_t length) WARN_UNUSED_RESULT;
 
 }  // namespace cast_crypto
 }  // namespace api