Revert "Add possibility to subclass Timer.Context (#1226)" (#1244)

This reverts commit 1bacf4d.

metrics-core/src/main/java/com/codahale/metrics/Timer.java

@@ -9,52 +9,41 @@
  * throughput statistics via {@link Meter}.
  */
 public class Timer implements Metered, Sampling {
-
     /**
      * A timing context.
      *
      * @see Timer#time()
      */
-    public interface Context extends AutoCloseable {
-
-        /**
-         * Updates the timer with the difference between current and start time. Call to this method will
-         * not reset the start time. Multiple calls result in multiple updates.
-         *
-         * @return the elapsed time in nanoseconds
-         */
-        long stop();
-
-        /**
-         * Equivalent to calling {@link #stop()}.
-         */
-        @Override
-        default void close() {
-            stop();
-        }
-    }
-
-    /**
-     * The default timing context.
-     */
-    private static class DefaultContext implements Context {
-
+    public static class Context implements AutoCloseable {
         private final Timer timer;
         private final Clock clock;
         private final long startTime;
 
-        private DefaultContext(Timer timer, Clock clock) {
+        private Context(Timer timer, Clock clock) {
             this.timer = timer;
             this.clock = clock;
             this.startTime = clock.getTick();
         }
 
-        @Override
+        /**
+         * Updates the timer with the difference between current and start time. Call to this method will
+         * not reset the start time. Multiple calls result in multiple updates.
+         *
+         * @return the elapsed time in nanoseconds
+         */
         public long stop() {
             final long elapsed = clock.getTick() - startTime;
             timer.update(elapsed, TimeUnit.NANOSECONDS);
             return elapsed;
         }
+
+        /**
+         * Equivalent to calling {@link #stop()}.
+         */
+        @Override
+        public void close() {
+            stop();
+        }
     }
 
     private final Meter meter;
@@ -158,7 +147,7 @@ public void time(Runnable event) {
      * @see Context
      */
     public Context time() {
-        return new DefaultContext(this, clock);
+        return new Context(this, clock);
     }
 
     @Override