[DevTools] Rework DevToolsSession interaction with domain handlers.

content/browser/devtools/forwarding_agent_host.h

Index: content/browser/devtools/forwarding_agent_host.h
diff --git a/content/browser/devtools/forwarding_agent_host.h b/content/browser/devtools/forwarding_agent_host.h
index c14ddb736615906bfa7ba120f471fdc69766e31e..8cd8c55c3d7a3c70f34373d0622ec439eeb41ef0 100644
--- a/content/browser/devtools/forwarding_agent_host.h
+++ b/content/browser/devtools/forwarding_agent_host.h
@@ -30,9 +30,11 @@ class ForwardingAgentHost
   void ConnectionClosed() override;
 
   // DevToolsAgentHostImpl implementation.
-  void Attach() override;
-  void Detach() override;
-  bool DispatchProtocolMessage(const std::string& message) override;
+  void Attach(DevToolsSession* session) override;
+  void Detach(DevToolsSession* session) override;
+  bool DispatchProtocolMessage(
+      DevToolsSession* session,
+      const std::string& message) override;
 
   // DevToolsAgentHost implementation
   std::string GetType() override;