tls: provide now value from C++

Instead of separately calling into C++ from JS to retrieve
the Timer.now() value, pass it in as an argument.

lib/_tls_wrap.js

@@ -32,7 +32,6 @@ const common = require('_tls_common');
 const { StreamWrap } = require('_stream_wrap');
 const { Buffer } = require('buffer');
 const debug = util.debuglog('tls');
-const { Timer } = process.binding('timer_wrap');
 const tls_wrap = process.binding('tls_wrap');
 const { TCP, constants: TCPConstants } = process.binding('tcp_wrap');
 const { Pipe, constants: PipeConstants } = process.binding('pipe_wrap');
@@ -49,14 +48,13 @@ const kSNICallback = Symbol('snicallback');
 
 const noop = () => {};
 
-function onhandshakestart() {
+function onhandshakestart(now) {
   debug('onhandshakestart');
 
-  const owner = this.owner;
-  const now = Timer.now();
-
   assert(now >= this.lastHandshakeTime);
 
+  const owner = this.owner;
+
   if ((now - this.lastHandshakeTime) >= tls.CLIENT_RENEG_WINDOW * 1000) {
     this.handshakes = 0;
   }

src/tls_wrap.cc

@@ -230,7 +230,8 @@ void TLSWrap::SSLInfoCallback(const SSL* ssl_, int where, int ret) {
   if (where & SSL_CB_HANDSHAKE_START) {
     Local<Value> callback = object->Get(env->onhandshakestart_string());
     if (callback->IsFunction()) {
-      c->MakeCallback(callback.As<Function>(), 0, nullptr);
+      Local<Value> argv[] = { env->GetNow() };
+      c->MakeCallback(callback.As<Function>(), arraysize(argv), argv);
     }
   }