[Devtools] Allow User-Agent header override for Websockets

content/browser/devtools/render_frame_devtools_agent_host.cc

Index: content/browser/devtools/render_frame_devtools_agent_host.cc
diff --git a/content/browser/devtools/render_frame_devtools_agent_host.cc b/content/browser/devtools/render_frame_devtools_agent_host.cc
index f2aaf5473993cb237a9574e3e07a857ae72a8881..4bd11c9ead2e7f89c9cd64e1cbec51065e505ad1 100644
--- a/content/browser/devtools/render_frame_devtools_agent_host.cc
+++ b/content/browser/devtools/render_frame_devtools_agent_host.cc
@@ -483,6 +483,12 @@ bool RenderFrameDevToolsAgentHost::DispatchProtocolMessage(
   return true;
 }
 
+std::string RenderFrameDevToolsAgentHost::GetUserAgentOverride() {
+  if (!current_)
+    return "";
+  return network_handler_->GetUserAgentOverride();
+}
+
 void RenderFrameDevToolsAgentHost::InspectElement(int x, int y) {
   if (current_)
     current_->InspectElement(x, y);
@@ -519,6 +525,7 @@ void RenderFrameDevToolsAgentHost::OnClientDetached() {
   service_worker_handler_->Detached();
   tracing_handler_->Detached();
   frame_trace_recorder_.reset();
+  network_handler_->Detached();
   in_navigation_protocol_message_buffer_.clear();
 
   // TODO(kaznacheev): Move this call back to DevToolsManager when