[DevTools] Rework DevToolsSession interaction with domain handlers.

content/browser/devtools/protocol/io_handler.h

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CONTENT_BROWSER_DEVTOOLS_PROTOCOL_IO_HANDLER_H_
 #define CONTENT_BROWSER_DEVTOOLS_PROTOCOL_IO_HANDLER_H_
 
 #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 {
 class RefCountedString;
 }
 
 namespace content {
 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.
   void Read(
       const std::string& handle,
       Maybe<int> offset,
       Maybe<int> max_size,
       std::unique_ptr<ReadCallback> callback) override;
   Response Close(const std::string& handle) override;
 
  private:
   void ReadComplete(std::unique_ptr<ReadCallback> callback,
       const scoped_refptr<base::RefCountedString>& data, int status);
 
   std::unique_ptr<IO::Frontend> frontend_;
   DevToolsIOContext* io_context_;
   base::WeakPtrFactory<IOHandler> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(IOHandler);
 };
 
 }  // namespace protocol
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_DEVTOOLS_PROTOCOL_TRACING_HANDLER_H_