Add ThreadChecker class to ThreadUtils

talk/app/webrtc/java/android/org/webrtc/ThreadUtils.java

 /*
  * libjingle
  * Copyright 2015 Google Inc.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are met:
  *
  *  1. Redistributions of source code must retain the above copyright notice,
  *     this list of conditions and the following disclaimer.
  *  2. Redistributions in binary form must reproduce the above copyright notice,
@@ skipping 13 matching lines @@
  * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 package org.webrtc;
 
 import java.util.concurrent.CountDownLatch;
 
 final class ThreadUtils {
   /**
+   * Utility class to be used for checking that a method is called on the correct thread.
+   */
+  public static class ThreadChecker {
+    private Thread thread = Thread.currentThread();
+
+    public void checkIsOnValidThread() {
+      if (thread == null) {
+        thread = Thread.currentThread();
+      }
+      if (Thread.currentThread() != thread) {
+        throw new IllegalStateException("Wrong thread");
+      }
+    }
+
+    public void detachThread() {
+      thread = null;
+    }
+  }
+
+  /**
    * Utility interface to be used with executeUninterruptibly() to wait for blocking operations
    * to complete without getting interrupted..
    */
   public interface BlockingOperation {
     void run() throws InterruptedException;
   }
 
   /**
    * Utility method to make sure a blocking operation is executed to completion without getting
    * interrupted. This should be used in cases where the operation is waiting for some critical
@@ skipping 30 matching lines @@
 
   public static void awaitUninterruptibly(final CountDownLatch latch) {
     executeUninterruptibly(new BlockingOperation() {
       @Override
       public void run() throws InterruptedException {
         latch.await();
       }
     });
   }
 }