[Devtools] Allow User-Agent header override for Websockets

net/websockets/websocket_channel.h

Index: net/websockets/websocket_channel.h
diff --git a/net/websockets/websocket_channel.h b/net/websockets/websocket_channel.h
index 002212b2f63009b86e9ee020f9192e4a3077d894..8e7e8c36866bb9391d7b05599ca6f48a8d8e02f4 100644
--- a/net/websockets/websocket_channel.h
+++ b/net/websockets/websocket_channel.h
@@ -50,6 +50,7 @@ class NET_EXPORT WebSocketChannel {
       const GURL&,
       const std::vector<std::string>&,
       const url::Origin&,
+      const std::string&,
       URLRequestContext*,
       const BoundNetLog&,
       std::unique_ptr<WebSocketStream::ConnectDelegate>)>
@@ -71,7 +72,8 @@ class NET_EXPORT WebSocketChannel {
   void SendAddChannelRequest(
       const GURL& socket_url,
       const std::vector<std::string>& requested_protocols,
-      const url::Origin& origin);
+      const url::Origin& origin,
+      const std::string& additional_headers);
 
   // Sends a data frame to the remote side. It is the responsibility of the
   // caller to ensure that they have sufficient send quota to send this data,
@@ -121,6 +123,7 @@ class NET_EXPORT WebSocketChannel {
       const GURL& socket_url,
       const std::vector<std::string>& requested_protocols,
       const url::Origin& origin,
+      const std::string& additional_headers,
       const WebSocketStreamCreator& creator);
 
   // The default timout for the closing handshake is a sensible value (see
@@ -213,6 +216,7 @@ class NET_EXPORT WebSocketChannel {
       const GURL& socket_url,
       const std::vector<std::string>& requested_protocols,
       const url::Origin& origin,
+      const std::string& additional_headers,
       const WebSocketStreamCreator& creator);
 
   // Success callback from WebSocketStream::CreateAndConnectStream(). Reports