[DevTools] Rework DevToolsSession interaction with domain handlers.

content/browser/devtools/protocol/emulation_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_EMULATION_HANDLER_H_
 #define CONTENT_BROWSER_DEVTOOLS_PROTOCOL_EMULATION_HANDLER_H_
 
 #include "base/macros.h"
+#include "content/browser/devtools/protocol/devtools_domain_handler.h"
 #include "content/browser/devtools/protocol/emulation.h"
 #include "third_party/WebKit/public/web/WebDeviceEmulationParams.h"
 
 namespace content {
 
 class RenderFrameHostImpl;
 class WebContentsImpl;
 
 namespace protocol {
 
-class EmulationHandler : public Emulation::Backend {
+class EmulationHandler : public DevToolsDomainHandler,
+                         public Emulation::Backend {
  public:
   EmulationHandler();
   ~EmulationHandler() override;
 
-  void SetRenderFrameHost(RenderFrameHostImpl* host);
-  void Wire(UberDispatcher*);
+  void Wire(UberDispatcher* dispatcher) override;
+  void SetRenderFrameHost(RenderFrameHostImpl* host) override;
   Response Disable() override;
 
   Response SetGeolocationOverride(Maybe<double> latitude,
                                   Maybe<double> longitude,
                                   Maybe<double> accuracy) override;
   Response ClearGeolocationOverride() override;
 
   Response SetTouchEmulationEnabled(bool enabled,
                                     Maybe<std::string> configuration) override;
 
@@ skipping 29 matching lines @@
 
   RenderFrameHostImpl* host_;
 
   DISALLOW_COPY_AND_ASSIGN(EmulationHandler);
 };
 
 }  // namespace protocol
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_DEVTOOLS_PROTOCOL_EMULATION_HANDLER_H_