Keep NaCl plugins used in app background pages alive when active.

components/nacl/browser/nacl_browser_delegate.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 COMPONENTS_NACL_BROWSER_NACL_BROWSER_DELEGATE_H_
 #define COMPONENTS_NACL_BROWSER_NACL_BROWSER_DELEGATE_H_
 
 #include <string>
 
 #include "base/callback_forward.h"
+#include "content/public/browser/browser_ppapi_host.h"
 
 class GURL;
 
 namespace base {
 class FilePath;
 }
 
 namespace ppapi {
 namespace host {
 class HostFactory;
 }
 }
 
-namespace content {
-class BrowserPpapiHost;
-}
-
 // Encapsulates the dependencies of NaCl code on chrome/, to avoid a direct
 // dependency on chrome/.
 class NaClBrowserDelegate {
  public:
   virtual ~NaClBrowserDelegate() {}
 
   // Show an infobar to the user.
   virtual void ShowNaClInfobar(int render_process_id, int render_view_id,
                                int error_id) = 0;
   // Returns whether dialogs are allowed. This is used to decide if to add the
@@ skipping 28 matching lines @@
   // otherwise non blocking API will be used (which only handles a subset of the
   // urls checking only the url scheme against kExtensionScheme).
   virtual bool MapUrlToLocalFilePath(const GURL& url,
                                      bool use_blocking_api,
                                      base::FilePath* file_path) = 0;
   // Set match patterns which will be checked before enabling debug stub.
   virtual void SetDebugPatterns(std::string debug_patterns) = 0;
 
   // Returns whether NaCl application with this manifest URL should be debugged.
   virtual bool URLMatchesDebugPatterns(const GURL& manifest_url) = 0;
+
+  // Returns a callback that handles NaCl idle state transitions.
+  virtual content::BrowserPpapiHost::OnKeepaliveCallback
+      GetOnKeepaliveCallback() = 0;
 };
 
 #endif  // COMPONENTS_NACL_BROWSER_NACL_BROWSER_DELEGATE_H_