7104147: the fix for cr6887286 was not appropriate for backporting

Summary: Memory leak in the list of ImageObservers watching an object. We use recursion to iterate over the list. So once the list gets too big, we overflow the stack. Fix is to execute a prune operation on ever add, so there is no way we can get indefinite growth of stale nodes.
Reviewed-by: prr, flar

src/share/classes/sun/awt/image/ImageWatched.java

 /*
- * Copyright (c) 1995, 2003, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1995, 2012, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -143,6 +143,7 @@ public abstract class ImageWatched {
         if (iw != null && !isWatcher(iw)) {
             watcherList = new WeakLink(iw, watcherList);
         }
+        watcherList = watcherList.removeWatcher(null);
     }
 
     public synchronized boolean isWatcher(ImageObserver iw) {

test/sun/awt/image/ImageWatched/AddNoLeak.java

+/*
+ * Copyright (c) 2012, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+import java.awt.image.ImageObserver;
+import java.awt.image.ImageProducer;
+import java.awt.image.ImageConsumer;
+import java.awt.Image;
+import java.awt.Container;
+
+/* @test 1.0 12/01/17
+   @bug 7104151
+   @summary Make sure that we don't leak image observers (or related objects)
+   @run main/othervm AddNoLeak
+   @author David Buck
+*/
+
+public class AddNoLeak {
+    public static void main(String[] args) {
+        System.setProperty("java.awt.headless", "true");
+        Container cont = new Container();
+        Image img = cont.createImage(new DummyImageSource());
+        for(int i=0;i < 15000;i++) {
+            img.getWidth(new ImageObserver() {
+                public boolean imageUpdate(Image img, int infoflags, int x, int y, int width, int height) {return false;}
+            });
+            if (i % 100 == 0) {
+                System.gc();
+            }
+        }
+    }
+
+    private static class DummyImageSource implements ImageProducer {
+        public void addConsumer(ImageConsumer ic){}
+        public boolean isConsumer(ImageConsumer ic){return false;}
+        public void removeConsumer(ImageConsumer ic){}
+        public void startProduction(ImageConsumer ic){}
+        public void requestTopDownLeftRightResend(ImageConsumer ic){}
+    }
+}