Fix comment typo.

ppapi/utility/completion_callback_factory_thread_traits.h

 // Copyright (c) 2012 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_UTILITY_THREAD_SAFE_THREAD_TRAITS_H_
 #define PPAPI_UTILITY_THREAD_SAFE_THREAD_TRAITS_H_
 
 #include "ppapi/cpp/logging.h"
 #include "ppapi/cpp/module.h"
 #include "ppapi/utility/threading/lock.h"
@@ skipping 100 matching lines @@
 
    private:
     int32_t ref_;
 #ifndef NDEBUG
     bool is_main_thread_;
 #endif
   };
 
   /// A simple object that acts like a lock but does nothing.
   ///
-  /// MStrong>Note:</strong> in Debug mode, it checks that it is either
+  /// <strong>Note:</strong> in Debug mode, it checks that it is either
   /// called on the main thread, or always called on another thread. It also
   /// asserts that the caller does not recursively lock.
   class Lock {
    public:
     Lock() {
 #ifndef NDEBUG
       is_main_thread_ = Module::Get()->core()->IsMainThread();
       lock_held_ = false;
 #endif
     }
@@ skipping 37 matching lines @@
     }
 
    private:
     Lock& lock_;
   };
 };
 
 }  // namespace pp
 
 #endif  // PPAPI_UTILITY_THREAD_SAFE_THREAD_TRAITS_H_