PNaCl on-demand installs: Make a separate async IPC to check if PNaCl is installed

chrome/browser/nacl_host/nacl_browser_delegate_impl.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 CHROME_BROWSER_NACL_HOST_NACL_BROWSER_DELEGATE_IMPL_H_
 #define CHROME_BROWSER_NACL_HOST_NACL_BROWSER_DELEGATE_IMPL_H_
 
 #include "base/compiler_specific.h"
 #include "components/nacl/common/nacl_browser_delegate.h"
 
 class NaClBrowserDelegateImpl : public NaClBrowserDelegate {
  public:
   NaClBrowserDelegateImpl() {}
   virtual ~NaClBrowserDelegateImpl() {}
 
   virtual void ShowNaClInfobar(int render_process_id, int render_view_id,
                                int error_id) OVERRIDE;
   virtual bool DialogsAreSuppressed() OVERRIDE;
   virtual bool GetCacheDirectory(base::FilePath* cache_dir) OVERRIDE;
   virtual bool GetPluginDirectory(base::FilePath* plugin_dir) OVERRIDE;
   virtual bool GetPnaclDirectory(base::FilePath* pnacl_dir) OVERRIDE;
   virtual bool GetUserDirectory(base::FilePath* user_dir) OVERRIDE;
   virtual std::string GetVersionString() const OVERRIDE;
   virtual ppapi::host::HostFactory* CreatePpapiHostFactory(
       content::BrowserPpapiHost* ppapi_host) OVERRIDE;
+  virtual void TryInstallPnacl(
+      const base::Callback<void(bool)>& installed) OVERRIDE;
 };
 
 
 #endif  // CHROME_BROWSER_NACL_HOST_NACL_BROWSER_DELEGATE_IMPL_H_