[DevTools] Rework DevToolsSession interaction with domain handlers.

content/browser/devtools/protocol/io_handler.h

Index: content/browser/devtools/protocol/io_handler.h
diff --git a/content/browser/devtools/protocol/io_handler.h b/content/browser/devtools/protocol/io_handler.h
index 647a270c6c1ba041e2a5f72695478f8bf31cf050..ef1d14edbfa2566fa905bb78719a1d2f8bbc3a31 100644
--- a/content/browser/devtools/protocol/io_handler.h
+++ b/content/browser/devtools/protocol/io_handler.h
@@ -7,6 +7,7 @@
 
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
+#include "content/browser/devtools/protocol/devtools_domain_handler.h"
 #include "content/browser/devtools/protocol/io.h"
 
 namespace base {
@@ -18,12 +19,14 @@ class DevToolsIOContext;
 
 namespace protocol {
 
-class IOHandler : public IO::Backend {
+class IOHandler : public DevToolsDomainHandler,
+                  public IO::Backend {
  public:
   explicit IOHandler(DevToolsIOContext* io_context);
   ~IOHandler() override;
 
-  void Wire(UberDispatcher*);
+  void Wire(UberDispatcher* dispatcher) override;
+  void SetRenderFrameHost(RenderFrameHostImpl* host) override;
   Response Disable() override;
 
   // Protocol methods.