Enable media.dll / libmedia.so.

media/base/callback.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.
 
 // Some basic utilities for aiding in the management of Tasks and Callbacks.
 //
 // AutoCallbackRunner is akin to scoped_ptr for callbacks.  It is useful for
 // ensuring a callback is executed and delete in the face of multiple return
 // points in a function.
 //
 // TaskToCallbackAdapter converts a Task to a Callback0::Type since the two type
 // hierarchies are strangely separate.
 //
 // CleanupCallback wraps another Callback and provides the ability to register
 // objects for deletion as well as cleanup tasks that will be run on the
 // callback's destruction.  The deletion and cleanup tasks will be run on
 // whatever thread the CleanupCallback is destroyed in.
 
 #ifndef MEDIA_BASE_CALLBACK_
 #define MEDIA_BASE_CALLBACK_
 
 #include <vector>
 
 #include "base/callback_old.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/task.h"
+#include "media/base/media_export.h"
 
 namespace media {
 
-class AutoCallbackRunner {
+class MEDIA_EXPORT AutoCallbackRunner {
  public:
   // Takes ownership of the callback.
   explicit AutoCallbackRunner(Callback0::Type* callback)
       : callback_(callback) {
   }
 
   ~AutoCallbackRunner();
 
   Callback0::Type* release() { return callback_.release(); }
 
@@ skipping 15 matching lines @@
   TaskToCallbackAdapter(Task* task);
 
   scoped_ptr<Task> task_;
 
   DISALLOW_COPY_AND_ASSIGN(TaskToCallbackAdapter);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_BASE_CALLBACK_