[DevTools] Rework DevToolsSession interaction with domain handlers.

content/browser/devtools/protocol/security_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_SECURITY_HANDLER_H_
 #define CONTENT_BROWSER_DEVTOOLS_PROTOCOL_SECURITY_HANDLER_H_
 
 #include "base/macros.h"
+#include "content/browser/devtools/protocol/devtools_domain_handler.h"
 #include "content/browser/devtools/protocol/security.h"
 #include "content/public/browser/web_contents_observer.h"
 
 namespace content {
 
 class RenderFrameHostImpl;
 
 namespace protocol {
 
-class SecurityHandler : public Security::Backend,
+class SecurityHandler : public DevToolsDomainHandler,
+                        public Security::Backend,
                         public WebContentsObserver {
  public:
   SecurityHandler();
   ~SecurityHandler() override;
 
-  void Wire(UberDispatcher*);
-  void SetRenderFrameHost(RenderFrameHostImpl* host);
+  void Wire(UberDispatcher* dispatcher) override;
+  void SetRenderFrameHost(RenderFrameHostImpl* host) override;
 
   Response Enable() override;
   Response Disable() override;
   Response ShowCertificateViewer() override;
 
  private:
   void AttachToRenderFrameHost();
 
   // WebContentsObserver overrides
   void DidChangeVisibleSecurityState() override;
 
   std::unique_ptr<Security::Frontend> frontend_;
   bool enabled_;
   RenderFrameHostImpl* host_;
 
   DISALLOW_COPY_AND_ASSIGN(SecurityHandler);
 };
 
 }  // namespace protocol
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_DEVTOOLS_PROTOCOL_SECURITY_HANDLER_H_