[DevTools] Support multiple sessions in Target domain

content/browser/devtools/devtools_agent_host_impl.cc

Index: content/browser/devtools/devtools_agent_host_impl.cc
diff --git a/content/browser/devtools/devtools_agent_host_impl.cc b/content/browser/devtools/devtools_agent_host_impl.cc
index 011befdc74880ebeb30ef3f93e971756e9db6896..6bd91c780f550149f4f4c1c5e52b87474672d533 100644
--- a/content/browser/devtools/devtools_agent_host_impl.cc
+++ b/content/browser/devtools/devtools_agent_host_impl.cc
@@ -187,6 +187,10 @@ void DevToolsAgentHostImpl::ForceAttachClient(DevToolsAgentHostClient* client) {
   InnerAttachClient(client);
 }
 
+void DevToolsAgentHostImpl::AttachMultiClient(DevToolsAgentHostClient* client) {
+  InnerAttachClient(client);
+}
+
 bool DevToolsAgentHostImpl::DetachClient(DevToolsAgentHostClient* client) {
   if (!SessionByClient(client))
     return false;