[DevTools] Support multiple clients in DevToolsAgentHost

content/browser/devtools/forwarding_agent_host.cc

Index: content/browser/devtools/forwarding_agent_host.cc
diff --git a/content/browser/devtools/forwarding_agent_host.cc b/content/browser/devtools/forwarding_agent_host.cc
index f87276fa0d92777403ca5404eb3f1d49ab8e1cee..ccf3c3dbfb9295c63e1224bd37eb61d31594e57f 100644
--- a/content/browser/devtools/forwarding_agent_host.cc
+++ b/content/browser/devtools/forwarding_agent_host.cc
@@ -22,12 +22,12 @@ ForwardingAgentHost::~ForwardingAgentHost() {
 }
 
 void ForwardingAgentHost::DispatchOnClientHost(const std::string& message) {
-  if (session())
-    session()->SendMessageToClient(message);
+  if (!sessions().empty())
+    sessions().begin()->second->SendMessageToClient(message);
 }
 
 void ForwardingAgentHost::ConnectionClosed() {
-  ForceDetach(false);
+  ForceDetachAllClients(false);
 }
 
 void ForwardingAgentHost::AttachSession(DevToolsSession* session) {
@@ -45,6 +45,12 @@ bool ForwardingAgentHost::DispatchProtocolMessage(
   return true;
 }
 
+bool ForwardingAgentHost::AttachMultiClient(DevToolsAgentHostClient* client) {
+  if (!sessions().empty())
+    return false;
+  return DevToolsAgentHostImpl::AttachMultiClient(client);
+}
+
 std::string ForwardingAgentHost::GetType() {
   return delegate_->GetType();
 }