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

content/public/browser/browser_ppapi_host.h

Index: content/public/browser/browser_ppapi_host.h
diff --git a/content/public/browser/browser_ppapi_host.h b/content/public/browser/browser_ppapi_host.h
index 45f997ea06b7705f62594948466ffcecab9cbb83..f5adeb71fdeba33758b6f90b068048f0a7efd076 100644
--- a/content/public/browser/browser_ppapi_host.h
+++ b/content/public/browser/browser_ppapi_host.h
@@ -34,6 +34,17 @@ namespace content {
 // lives entirely on the I/O thread.
 class CONTENT_EXPORT BrowserPpapiHost {
  public:
+  struct OnKeepaliveInstanceStruct {
+    int render_process_id;
+    int render_view_id;
+    GURL document_url;
+  };
+  typedef std::vector<OnKeepaliveInstanceStruct> OnKeepaliveInstanceData;
+  typedef base::Callback<
+      void (const OnKeepaliveInstanceData& intance_data,
+            const base::FilePath& profile_data_directory)>
+      OnKeepaliveCallback;
+
   // Creates a browser host and sets up an out-of-process proxy for an external
   // pepper plugin process.
   static BrowserPpapiHost* CreateExternalPluginProcess(
@@ -81,6 +92,10 @@ class CONTENT_EXPORT BrowserPpapiHost {
   // Get the Document/Plugin URLs for the given PP_Instance.
   virtual GURL GetDocumentURLForInstance(PP_Instance instance) = 0;
   virtual GURL GetPluginURLForInstance(PP_Instance instance) = 0;
+
+  // Sets a callback the BrowserPpapiHost will run when the plugin messages
+  // that it is active.
+  virtual void SetOnKeepaliveCallback(const OnKeepaliveCallback& callback) = 0;
 };
 
 }  // namespace content