Create stubs for system certificate validation.

net/net.gyp

Index: net/net.gyp
diff --git a/net/net.gyp b/net/net.gyp
index 44983cf84627e57217056978a95b1eb0b418a2d2..d174ba683f9f5ea8bb20c2e24ea3a9ca2c9094dd 100644
--- a/net/net.gyp
+++ b/net/net.gyp
@@ -70,6 +70,14 @@
         'base/cert_status_flags.h',
         'base/cert_verifier.cc',
         'base/cert_verifier.h',
+        'base/cert_verify_proc_mac.cc',
+        'base/cert_verify_proc_mac.h',
+        'base/cert_verify_proc_nss.cc',
+        'base/cert_verify_proc_nss.h',
+        'base/cert_verify_proc_openssl.cc',
+        'base/cert_verify_proc_openssl.h',
+        'base/cert_verify_proc_win.cc',
+        'base/cert_verify_proc_win.h',
         'base/cert_verify_result.cc',
         'base/cert_verify_result.h',
         'base/completion_callback.h',
@@ -812,6 +820,7 @@
         ['use_openssl==1', {
             'sources!': [
               'base/cert_database_nss.cc',
+              'base/cert_verify_proc_nss.cc',
               'base/crypto_module_nss.cc',
               'base/dnssec_keyset.cc',
               'base/dnssec_keyset.h',
@@ -843,6 +852,7 @@
           {  # else !use_openssl: remove the unneeded files
             'sources!': [
               'base/cert_database_openssl.cc',
+              'base/cert_verify_proc_openssl.cc',
               'base/crypto_module_openssl.cc',
               'base/keygen_handler_openssl.cc',
               'base/openssl_memory_private_key_store.cc',