[DevTools] Use InspectorFrontendHost.readyForTest for layout tests.

content/shell/browser/shell_devtools_frontend.h

 // Copyright 2013 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_SHELL_BROWSER_SHELL_DEVTOOLS_FRONTEND_H_
 #define CONTENT_SHELL_BROWSER_SHELL_DEVTOOLS_FRONTEND_H_
 
 #include "base/compiler_specific.h"
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
@@ skipping 37 matching lines @@
 
  protected:
   ShellDevToolsFrontend(Shell* frontend_shell, WebContents* inspected_contents);
   ~ShellDevToolsFrontend() override;
 
   // content::DevToolsAgentHostClient implementation.
   void AgentHostClosed(DevToolsAgentHost* agent_host, bool replaced) override;
   void DispatchProtocolMessage(DevToolsAgentHost* agent_host,
                                const std::string& message) override;
   base::DictionaryValue* preferences() { return &preferences_; }
+  virtual void HandleMessageFromDevToolsFrontend(const std::string& message);
 
  private:
   // WebContentsObserver overrides
   void RenderViewCreated(RenderViewHost* render_view_host) override;
   void DocumentAvailableInMainFrame() override;
   void WebContentsDestroyed() override;
 
-  void HandleMessageFromDevToolsFrontend(const std::string& message);
-
   // net::URLFetcherDelegate overrides.
   void OnURLFetchComplete(const net::URLFetcher* source) override;
 
   void SendMessageAck(int request_id,
                       const base::Value* arg1);
 
   Shell* frontend_shell_;
   WebContents* inspected_contents_;
   scoped_refptr<DevToolsAgentHost> agent_host_;
   scoped_ptr<DevToolsFrontendHost> frontend_host_;
   using PendingRequestsMap = std::map<const net::URLFetcher*, int>;
   PendingRequestsMap pending_requests_;
   base::DictionaryValue preferences_;
   base::WeakPtrFactory<ShellDevToolsFrontend> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(ShellDevToolsFrontend);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_SHELL_BROWSER_SHELL_DEVTOOLS_FRONTEND_H_