Add an out parameter to VerifyCertificateChain for retrieving the trusted chain.

net/cert/internal/verify_certificate_chain_unittest.cc

Index: net/cert/internal/verify_certificate_chain_unittest.cc
diff --git a/net/cert/internal/verify_certificate_chain_unittest.cc b/net/cert/internal/verify_certificate_chain_unittest.cc
index 11323f8bc75035078fa0f18810c310ef942b5e02..aaec56fd9951b0dc7e17a828b1592a1da484f944 100644
--- a/net/cert/internal/verify_certificate_chain_unittest.cc
+++ b/net/cert/internal/verify_certificate_chain_unittest.cc
@@ -114,8 +114,18 @@ void RunTest(const char* file_name) {
 
   SimpleSignaturePolicy signature_policy(1024);
 
-  bool result =
-      VerifyCertificateChain(input_chain, trust_store, &signature_policy, time);
+  std::vector<scoped_refptr<ParsedCertificate>> trusted_chain;
+  bool result = VerifyCertificateChain(input_chain, trust_store,
+                                       &signature_policy, time, &trusted_chain);
+  if (result) {
+    ASSERT_EQ(trusted_chain.size(), input_chain.size() + 1);

[eroman, 2016/06/16 22:55:01]

This is true for most if not all the tests.
I guess run the tests and see if this works :)

It is possible we also have a test where the input chain contained the trust
anchor -- I don't remember if I added that as part of these unit tests or
elsewhere...

If that is the case you may need to relax this to allow for both possibilities.

[ryanchung, 2016/06/16 23:13:09]

All tests passed locally. Will let try bot confirm.

+    ASSERT_TRUE(std::equal(input_chain.begin(),
+                           input_chain.begin() + input_chain.size(),

[eroman, 2016/06/16 22:55:01]

nit: input_chain.end()

[ryanchung, 2016/06/16 23:13:09]

Done.

+                           trusted_chain.begin()));
+    ASSERT_TRUE(trust_store.IsTrustedCertificate(trusted_chain.back().get()));
+  } else {
+    ASSERT_EQ(trusted_chain.size(), 0u);
+  }
 
   ASSERT_EQ(expected_result, result);
 }
@@ -235,8 +245,8 @@ TEST(VerifyCertificateChainTest, EmptyChainIsInvalid) {
   std::vector<scoped_refptr<ParsedCertificate>> chain;
   SimpleSignaturePolicy signature_policy(2048);
 
-  ASSERT_FALSE(
-      VerifyCertificateChain(chain, trust_store, &signature_policy, time));
+  ASSERT_FALSE(VerifyCertificateChain(chain, trust_store, &signature_policy,
+                                      time, nullptr));
 }
 
 // TODO(eroman): Add test that invalidate validity dates where the day or month