DevTools: introduce browser domain for basic target discovery.

chrome/browser/extensions/api/debugger/debugger_api.cc

Index: chrome/browser/extensions/api/debugger/debugger_api.cc
diff --git a/chrome/browser/extensions/api/debugger/debugger_api.cc b/chrome/browser/extensions/api/debugger/debugger_api.cc
index 35602f46174aa9faf581fff1dba7086ee571d0b1..e3529e0e28c24a85da61476d9afd12a5ca68658d 100644
--- a/chrome/browser/extensions/api/debugger/debugger_api.cc
+++ b/chrome/browser/extensions/api/debugger/debugger_api.cc
@@ -367,7 +367,7 @@ void ExtensionDevToolsClientHost::AgentHostClosed(
 }
 
 void ExtensionDevToolsClientHost::Close() {
-  agent_host_->DetachClient();
+  agent_host_->DetachClient(this);
   delete this;
 }
 
@@ -387,7 +387,7 @@ void ExtensionDevToolsClientHost::SendMessageToBackend(
 
   std::string json_args;
   base::JSONWriter::Write(protocol_request, &json_args);
-  agent_host_->DispatchProtocolMessage(json_args);
+  agent_host_->DispatchProtocolMessage(this, json_args);
 }
 
 void ExtensionDevToolsClientHost::InfoBarDismissed() {