Move JoinString to the base namespace

net/websockets/websocket_basic_handshake_stream.cc

Index: net/websockets/websocket_basic_handshake_stream.cc
diff --git a/net/websockets/websocket_basic_handshake_stream.cc b/net/websockets/websocket_basic_handshake_stream.cc
index 616dbb1d0f79f14741b6816145af384ef896bf0c..a253e2e49f4a13d31bdd935de7b1625f426136b2 100644
--- a/net/websockets/websocket_basic_handshake_stream.cc
+++ b/net/websockets/websocket_basic_handshake_stream.cc
@@ -99,7 +99,7 @@ void AddVectorHeaderIfNonEmpty(const char* name,
                                HttpRequestHeaders* headers) {
   if (value.empty())
     return;
-  headers->SetHeader(name, JoinString(value, ", "));
+  headers->SetHeader(name, base::JoinString(value, ", "));
 }
 
 GetHeaderResult GetSingleHeaderValue(const HttpResponseHeaders* headers,
@@ -346,7 +346,7 @@ bool ValidateExtensions(const HttpResponseHeaders* headers,
       }
     }
   }
-  *accepted_extensions_descriptor = JoinString(header_values, ", ");
+  *accepted_extensions_descriptor = base::JoinString(header_values, ", ");
   return true;
 }