Implement crypto signature verification routines using OpenSSL.

extensions/extensions.gyp

Index: extensions/extensions.gyp
diff --git a/extensions/extensions.gyp b/extensions/extensions.gyp
index b4932e76bea3cc5cd63d201ce02c32c81751532d..01248b9a5ddab34368b60024bf16de4b4f15865a 100644
--- a/extensions/extensions.gyp
+++ b/extensions/extensions.gyp
@@ -1244,6 +1244,11 @@
             '../base/allocator/allocator.gyp:allocator',
           ],
         }],
+        ['use_openssl==1', {
+          'sources': [
+            'browser/api/cast_channel/cast_auth_util_openssl_unittest.cc',
+          ]
+        }],
       ],
     },
   ]