Remove redundant DevToolsManager methods and clean up its clients.

content/public/browser/devtools_agent_host.h

 // Copyright (c) 2012 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_PUBLIC_BROWSER_DEVTOOLS_AGENT_HOST_H_
 #define CONTENT_PUBLIC_BROWSER_DEVTOOLS_AGENT_HOST_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 34 matching lines @@
   static std::string DisconnectRenderViewHost(RenderViewHost* rvh);
 
   // Reattaches agent host detached with DisconnectRenderViewHost method above
   // to |rvh|.
   static void ConnectRenderViewHost(const std::string& agent_host_cookie,
                                     RenderViewHost* rvh);
 
   // Returns a list of all existing RenderViewHost's that can be debugged.
   static std::vector<RenderViewHost*> GetValidRenderViewHosts();
 
+  // Returns true if there is a client attached.
+  virtual bool IsAttached() = 0;
+
   // Starts inspecting element at position (|x|, |y|) in the specified page.
   virtual void InspectElement(int x, int y) = 0;
 
   // Returns the unique id of the agent.
   virtual std::string GetId() = 0;
 
   // Returns render view host instance for this host if any.
   virtual RenderViewHost* GetRenderViewHost() = 0;
 
  protected:
   friend class base::RefCounted<DevToolsAgentHost>;
   virtual ~DevToolsAgentHost() {}
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_BROWSER_DEVTOOLS_AGENT_HOST_H_