Use base::Optional for handshake_challenge_for_testing_.

Change-Id: I2c14a7c94d55b38b303a6b827fd5d1d06a8feca4
Reviewed-on: https://chromium-review.googlesource.com/946151
Commit-Queue: Adam Rice <ricea@chromium.org>
Reviewed-by: Adam Rice <ricea@chromium.org>
Cr-Commit-Position: refs/heads/master@{#540793}

net/websockets/websocket_basic_handshake_stream.cc

@@ -342,8 +342,8 @@ int WebSocketBasicHandshakeStream::SendRequest(
   HttpRequestHeaders enriched_headers;
   enriched_headers.CopyFrom(headers);
   std::string handshake_challenge;
-  if (handshake_challenge_for_testing_) {
-    handshake_challenge = *handshake_challenge_for_testing_;
+  if (handshake_challenge_for_testing_.has_value()) {
+    handshake_challenge = handshake_challenge_for_testing_.value();
     handshake_challenge_for_testing_.reset();
   } else {
     handshake_challenge = GenerateHandshakeChallenge();
@@ -508,7 +508,7 @@ std::unique_ptr<WebSocketStream> WebSocketBasicHandshakeStream::Upgrade() {
 
 void WebSocketBasicHandshakeStream::SetWebSocketKeyForTesting(
     const std::string& key) {
-  handshake_challenge_for_testing_.reset(new std::string(key));
+  handshake_challenge_for_testing_ = key;
 }
 
 void WebSocketBasicHandshakeStream::ReadResponseHeadersCallback(

net/websockets/websocket_basic_handshake_stream.h

@@ -13,6 +13,7 @@
 
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
+#include "base/optional.h"
 #include "net/base/completion_once_callback.h"
 #include "net/base/net_export.h"
 #include "net/http/http_basic_state.h"
@@ -122,7 +123,7 @@ class NET_EXPORT_PRIVATE WebSocketBasicHandshakeStream
 
   // The key to be sent in the next Sec-WebSocket-Key header. Usually NULL (the
   // key is generated on the fly).
-  std::unique_ptr<std::string> handshake_challenge_for_testing_;
+  base::Optional<std::string> handshake_challenge_for_testing_;
 
   // The required value for the Sec-WebSocket-Accept header.
   std::string handshake_challenge_response_;