Add initial code for verifying a certificate chain.

net/net.gypi

Index: net/net.gypi
diff --git a/net/net.gypi b/net/net.gypi
index 616ec45d59e012d21249bd281e45013822bfde48..d2726511550fe0b794f712eef7347b508b10313f 100644
--- a/net/net.gypi
+++ b/net/net.gypi
@@ -105,6 +105,8 @@
       'cert/internal/verify_name_match.h',
       'cert/internal/verify_signed_data.cc',
       'cert/internal/verify_signed_data.h',
+      'cert/internal/verify_certificate_chain.cc',
+      'cert/internal/verify_certificate_chain.h',
       'cert/pem_tokenizer.cc',
       'cert/pem_tokenizer.h',
       'cert/sha256_legacy_support_win.cc',
@@ -1336,6 +1338,7 @@
       'cert/internal/signature_algorithm_unittest.cc',
       'cert/internal/test_helpers.cc',
       'cert/internal/test_helpers.h',
+      'cert/internal/verify_certificate_chain_unittest.cc',
       'cert/internal/verify_name_match_unittest.cc',
       'cert/internal/verify_signed_data_unittest.cc',
       'cert/jwk_serializer_unittest.cc',