Enable exporting SSLKEYLOGFILE on Android w/ command line arguments

net/socket/ssl_client_socket_openssl.cc

Index: net/socket/ssl_client_socket_openssl.cc
diff --git a/net/socket/ssl_client_socket_openssl.cc b/net/socket/ssl_client_socket_openssl.cc
index 1e0d799e6a731167e86489a9449142eb78752a91..f5a260c64749b2db6073ca5f4eb01a17d82b0684 100644
--- a/net/socket/ssl_client_socket_openssl.cc
+++ b/net/socket/ssl_client_socket_openssl.cc
@@ -472,6 +472,24 @@ SSLClientSocketOpenSSL::~SSLClientSocketOpenSSL() {
   Disconnect();
 }
 
+void SSLClientSocketOpenSSL::SetSslKeyLogFile(std::string ssl_keylog_file) {
+  std::string env_keylog_file;
+  scoped_ptr<base::Environment> env(base::Environment::Create());

[Bryan McQuade, 2015/10/14 00:38:54]

I think there's some benefit to centralizing the logic that decides what
filename to use here, and moving the env lookup to the code you've added in
io_thread.cc (and also removing the env lookup logic in the SSLContext
constructor). The logic in io_thread.cc could do something like:

1. check to see if env variable is set. if so, use it (pass its value to
SSLClientSocketOpenSSL::SetSSLKeyLogFile)
2. if env variable not set, check to see if command line flag is set. if so, use
it.
(and we may wish to log a warning if both the env variable and command line flag
are set to different values)

+  if (env->GetVar("SSLKEYLOGFILE", &env_keylog_file) &&
+      !env_keylog_file.empty()) {
+    return;
+  }
+
+  crypto::OpenSSLErrStackTracer err_tracer(FROM_HERE);
+  BIO* bio = BIO_new_file(ssl_keylog_file.c_str(), "a");
+  if (!bio) {
+    LOG(ERROR) << "Failed to open " << ssl_keylog_file;
+    ERR_print_errors_cb(&LogErrorCallback, NULL);
+  } else {
+    SSL_CTX_set_keylog_bio(SSLContext::GetInstance()->ssl_ctx(), bio);
+  }
+}
+
 void SSLClientSocketOpenSSL::GetSSLCertRequestInfo(
     SSLCertRequestInfo* cert_request_info) {
   cert_request_info->host_and_port = host_and_port_;