[DevTools] Rework DevToolsSession interaction with domain handlers.

content/browser/devtools/protocol/target_handler.h

 // Copyright 2016 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_TARGET_HANDLER_H_
 #define CONTENT_BROWSER_DEVTOOLS_PROTOCOL_TARGET_HANDLER_H_
 
 #include <map>
 #include <set>
 
+#include "content/browser/devtools/protocol/devtools_domain_handler.h"
 #include "content/browser/devtools/protocol/target.h"
 #include "content/browser/devtools/service_worker_devtools_manager.h"
 #include "content/public/browser/devtools_agent_host_client.h"
 #include "content/public/browser/devtools_agent_host_observer.h"
 
 namespace content {
 
 class RenderFrameHostImpl;
 
 namespace protocol {
 
-class TargetHandler : public Target::Backend,
+class TargetHandler : public DevToolsDomainHandler,
+                      public Target::Backend,
                       public DevToolsAgentHostClient,
                       public ServiceWorkerDevToolsManager::Observer,
                       public DevToolsAgentHostObserver {
  public:
   TargetHandler();
   ~TargetHandler() override;
 
-  void Wire(UberDispatcher*);
-  void SetRenderFrameHost(RenderFrameHostImpl* render_frame_host);
+  void Wire(UberDispatcher* dispatcher) override;
+  void SetRenderFrameHost(RenderFrameHostImpl* host) override;
   Response Disable() override;
 
   void UpdateServiceWorkers();
   void UpdateFrames();
 
   // Domain implementation.
   Response SetDiscoverTargets(bool discover) override;
   Response SetAutoAttach(bool auto_attach,
                          bool wait_for_debugger_on_start) override;
   Response SetAttachToFrames(bool value) override;
@@ skipping 64 matching lines @@
   std::set<GURL> frame_urls_;
   RawHostsMap reported_hosts_;
 
   DISALLOW_COPY_AND_ASSIGN(TargetHandler);
 };
 
 }  // namespace protocol
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_DEVTOOLS_PROTOCOL_TARGET_HANDLER_H_