Keep the module in scope when executing scripts. This prevents a crash when the

ppapi/proxy/host_dispatcher.h

 // Copyright (c) 2011 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 PPAPI_PROXY_HOST_DISPATCHER_H_
 #define PPAPI_PROXY_HOST_DISPATCHER_H_
 
 #include <map>
 #include <string>
 #include <vector>
@@ skipping 103 matching lines @@
   // Set to true when the plugin is in a state that it can be reentered by a
   // sync message from the host. We allow reentrancy only when we're processing
   // a sync message from the renderer that is a scripting command. When the
   // plugin is in this state, it needs to accept reentrancy since scripting may
   // ultimately call back into the plugin.
   bool allow_plugin_reentrancy_;
 
   DISALLOW_COPY_AND_ASSIGN(HostDispatcher);
 };
 
+// Create this object on the stack to prevent the module (and hence the
+// dispatcher) from being deleted out from under you. This is necessary when
+// calling some scripting functions that may delete the plugin.
+//
+// This may only be called in the host. The parameter is a plain Dispatcher
+// since that's what most callers have.
+class ScopedModuleReference {
+ public:
+  ScopedModuleReference(Dispatcher* dispatcher);
+  ~ScopedModuleReference();
+
+ private:
+  HostDispatcher* dispatcher_;
+
+  DISALLOW_COPY_AND_ASSIGN(ScopedModuleReference);
+};
+
 }  // namespace proxy
 }  // namespace pp
 
 #endif  // PPAPI_PROXY_HOST_DISPATCHER_H_