Use ReaderWriterLockSlim in System.Composition

Author: dsplaisted

src/System.Composition.Convention/src/Microsoft/Internal/Lock.cs

@@ -11,7 +11,6 @@ namespace Microsoft.Internal
 {
     internal sealed class Lock : IDisposable
     {
-#if FEATURE_SLIMLOCK
         private readonly ReaderWriterLockSlim _thisLock = new ReaderWriterLockSlim(LockRecursionPolicy.NoRecursion);
         private int _isDisposed = 0;
         public void EnterReadLock()
@@ -41,39 +40,5 @@ public void Dispose()
                 _thisLock.Dispose();
             }
         }
-
-#else
-        // ReaderWriterLockSlim is not yet implemented on SilverLight
-        // Satisfies our requirements until it is implemented
-        private readonly object _thisLock = new object();
-
-        public Lock()
-        {
-        }
-
-        public void EnterReadLock()
-        {
-            Monitor.Enter(_thisLock);
-        }
-
-        public void EnterWriteLock()
-        {
-            Monitor.Enter(_thisLock);
-        }
-
-        public void ExitReadLock()
-        {
-            Monitor.Exit(_thisLock);
-        }
-
-        public void ExitWriteLock()
-        {
-            Monitor.Exit(_thisLock);
-        }
-
-        public void Dispose()
-        {
-        }
-#endif //FEATURE_SLIMLOCK
     }
 }