[DevTools] Migrate from AgentStateCallbacks to DevToolsAgentHostObserver.

chrome/browser/devtools/chrome_devtools_manager_delegate.h

 // Copyright 2014 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 CHROME_BROWSER_DEVTOOLS_CHROME_DEVTOOLS_MANAGER_DELEGATE_H_
 #define CHROME_BROWSER_DEVTOOLS_CHROME_DEVTOOLS_MANAGER_DELEGATE_H_
 
 #include <memory>
 #include <set>
 
 #include "base/compiler_specific.h"
 #include "base/macros.h"
 #include "chrome/browser/devtools/device/devtools_android_bridge.h"
+#include "content/public/browser/devtools_agent_host_observer.h"
 #include "content/public/browser/devtools_manager_delegate.h"
 #include "net/base/host_port_pair.h"
 
 class DevToolsNetworkProtocolHandler;
 
-class ChromeDevToolsManagerDelegate : public content::DevToolsManagerDelegate {
+class ChromeDevToolsManagerDelegate :
+    public content::DevToolsManagerDelegate,
+    public content::DevToolsAgentHostObserver {
  public:
   static char kTypeApp[];
   static char kTypeBackgroundPage[];
   static char kTypeWebView[];
 
   ChromeDevToolsManagerDelegate();
   ~ChromeDevToolsManagerDelegate() override;
 
+ private:
   // content::DevToolsManagerDelegate implementation.
   void Inspect(content::DevToolsAgentHost* agent_host) override;
-  void DevToolsAgentStateChanged(content::DevToolsAgentHost* agent_host,
-                                 bool attached) override;
   bool DiscoverTargets(
       const content::DevToolsAgentHost::DiscoveryCallback& callback) override;
   base::DictionaryValue* HandleCommand(
       content::DevToolsAgentHost* agent_host,
       base::DictionaryValue* command_dict) override;
   std::string GetTargetType(content::RenderFrameHost* host) override;
   std::string GetTargetTitle(content::RenderFrameHost* host) override;
   scoped_refptr<content::DevToolsAgentHost> CreateNewTarget(
       const GURL& url) override;
   std::string GetDiscoveryPageHTML() override;
   std::string GetFrontendResource(const std::string& path) override;
 
- private:
+  // content::DevToolsAgentHostObserver overrides.
+  void DevToolsAgentHostAttached(
+      content::DevToolsAgentHost* agent_host) override;
+  void DevToolsAgentHostDetached(
+      content::DevToolsAgentHost* agent_host) override;
+
   void DevicesAvailable(
     const content::DevToolsAgentHost::DiscoveryCallback& callback,
     const DevToolsAndroidBridge::CompleteDevices& devices);
 
   std::unique_ptr<base::DictionaryValue> SetRemoteLocations(
       content::DevToolsAgentHost* agent_host,
       int command_id,
       base::DictionaryValue* params);
 
   std::unique_ptr<DevToolsNetworkProtocolHandler> network_protocol_handler_;
   std::unique_ptr<AndroidDeviceManager> device_manager_;
   std::set<net::HostPortPair> tcp_locations_;
 
   DISALLOW_COPY_AND_ASSIGN(ChromeDevToolsManagerDelegate);
 };
 
 #endif  // CHROME_BROWSER_DEVTOOLS_CHROME_DEVTOOLS_MANAGER_DELEGATE_H_