Add missing ProgressAdapter class

Bug 561360: Missing org.eclipse.swt.browser.ProgressAdapter
https://bugs.eclipse.org/bugs/show_bug.cgi?id=561360

Change-Id: I1f10044f59578823803448a0660a583c1dd6baff
diff --git a/bundles/org.eclipse.rap.rwt/src/org/eclipse/swt/browser/ProgressAdapter.java b/bundles/org.eclipse.rap.rwt/src/org/eclipse/swt/browser/ProgressAdapter.java
new file mode 100644
index 0000000..c11b8f0
--- /dev/null
+++ b/bundles/org.eclipse.rap.rwt/src/org/eclipse/swt/browser/ProgressAdapter.java
@@ -0,0 +1,41 @@
+/*******************************************************************************
+ * Copyright (c) 2003, 2016 IBM Corporation and others.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ *
+ * Contributors:
+ *     IBM Corporation - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.swt.browser;
+
+/**
+ * This adapter class provides default implementations for the
+ * methods described by the {@link ProgressListener} interface.
+ * <p>
+ * Classes that wish to deal with {@link ProgressEvent}'s can
+ * extend this class and override only the methods which they are
+ * interested in.
+ * </p>
+ * <p>
+ * An alternative to this class are the static helper methods in
+ * {@link ProgressListener},
+ * which accept a lambda expression or a method reference that implements the event consumer.
+ * </p>
+ *
+ * @see <a href="http://www.eclipse.org/swt/">Sample code and further information</a>
+ *
+ * @since 3.0
+ */
+public abstract class ProgressAdapter implements ProgressListener {
+
+  @Override
+  public void changed( ProgressEvent event ) {
+  }
+
+  @Override
+  public void completed( ProgressEvent event ) {
+  }
+
+}