| Index: media/blink/webcontentdecryptionmodulesession_impl.h
 | 
| diff --git a/media/blink/webcontentdecryptionmodulesession_impl.h b/media/blink/webcontentdecryptionmodulesession_impl.h
 | 
| index a9a3649013cb85eb883e8f75420bce4f89e0b8ba..18c94918c8a04a709db2a4de30afe8d651f0321e 100644
 | 
| --- a/media/blink/webcontentdecryptionmodulesession_impl.h
 | 
| +++ b/media/blink/webcontentdecryptionmodulesession_impl.h
 | 
| @@ -12,6 +12,7 @@
 | 
|  #include "base/callback.h"
 | 
|  #include "base/memory/ref_counted.h"
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|  #include "base/memory/weak_ptr.h"
 | 
| +#include "base/threading/thread_checker.h"
 | 
|  #include "media/base/media_keys.h"
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|  #include "third_party/WebKit/public/platform/WebContentDecryptionModuleSession.h"
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|  #include "third_party/WebKit/public/platform/WebString.h"
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| @@ -74,6 +75,7 @@ class WebContentDecryptionModuleSessionImpl
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|    // closed() event.
 | 
|    bool is_closed_;
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|  
 | 
| +  base::ThreadChecker thread_checker_;
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|    // Since promises will live until they are fired, use a weak reference when
 | 
|    // creating a promise in case this class disappears before the promise
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|    // actually fires.
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| 
 |