DevTools: introduce browser domain for basic target discovery.

components/devtools_http_handler/devtools_http_handler.cc

Index: components/devtools_http_handler/devtools_http_handler.cc
diff --git a/components/devtools_http_handler/devtools_http_handler.cc b/components/devtools_http_handler/devtools_http_handler.cc
index a5b173afcc4f48540e7883de704010db2e0f7892..89325284a9fd948a77fa1f4fd2e8e5939628294e 100644
--- a/components/devtools_http_handler/devtools_http_handler.cc
+++ b/components/devtools_http_handler/devtools_http_handler.cc
@@ -277,7 +277,7 @@ class DevToolsAgentHostClientImpl : public DevToolsAgentHostClient {
   ~DevToolsAgentHostClientImpl() override {
     DCHECK_CURRENTLY_ON(BrowserThread::UI);
     if (agent_host_.get())
-      agent_host_->DetachClient();
+      agent_host_->DetachClient(this);
   }
 
   void AgentHostClosed(DevToolsAgentHost* agent_host,
@@ -312,7 +312,7 @@ class DevToolsAgentHostClientImpl : public DevToolsAgentHostClient {
   void OnMessage(const std::string& message) {
     DCHECK_CURRENTLY_ON(BrowserThread::UI);
     if (agent_host_.get())
-      agent_host_->DispatchProtocolMessage(message);
+      agent_host_->DispatchProtocolMessage(this, message);
   }
 
  private: