content: Terminate early if the toolkit initialization fails.

content/public/browser/browser_main_runner.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_BROWSER_MAIN_RUNNER_H_
 #define CONTENT_PUBLIC_BROWSER_BROWSER_MAIN_RUNNER_H_
 
 #include "base/basictypes.h"
 #include "content/common/content_export.h"
 
 namespace content {
 
 struct MainFunctionParams;
 
 // This class is responsible for browser initialization, running and shutdown.
 class CONTENT_EXPORT BrowserMainRunner {
  public:
   virtual ~BrowserMainRunner() {}
 
   // Create a new BrowserMainRunner object.
   static BrowserMainRunner* Create();
 
   // Initialize all necessary browser state. The |parameters| values will be
-  // copied.
+  // copied. Returning a non-negative value indicates that initialization
+  // failed, and the returned value is used as the exit code for the process.
   virtual int Initialize(const content::MainFunctionParams& parameters) = 0;
 
   // Perform the default run logic.
   virtual int Run() = 0;
 
   // Shut down the browser state.
   virtual void Shutdown() = 0;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_BROWSER_BROWSER_MAIN_RUNNER_H_