--- old/src/jdk.internal.vm.compiler/share/classes/org.graalvm.compiler.debug/src/org/graalvm/compiler/debug/DebugDumpHandler.java	2017-07-07 09:29:53.000000000 -0700
+++ new/src/jdk.internal.vm.compiler/share/classes/org.graalvm.compiler.debug/src/org/graalvm/compiler/debug/DebugDumpHandler.java	2017-07-07 09:29:52.000000000 -0700
@@ -24,23 +24,34 @@
 
 import java.io.Closeable;
 
-public interface DebugDumpHandler extends Closeable {
-
-    void dump(Object object, String format, Object... arguments);
+/**
+ * Interface implemented by classes that provide an external visualization of selected object types
+ * such as compiler graphs and nodes. The format and client required to consume the visualizations
+ * is determined by the implementation. For example, a dumper may convert a compiler node to a human
+ * readable string and print it to the console. A more sophisticated dumper may serialize a compiler
+ * graph and send it over the network to a tool (e.g., https://github.com/graalvm/visualizer) that
+ * can display graphs.
+ */
+public interface DebugDumpHandler extends Closeable, DebugHandler {
 
     /**
-     * Add arbitrary capability for use by the handler.
+     * If the type of {@code object} is supported by this dumper, then a representation of
+     * {@code object} is sent to some consumer in a format determined by this object.
      *
-     * @param capability
+     * @param debug the debug context requesting the dump
+     * @param object the object to be dumped
+     * @param format a format string specifying a title that describes the context of the dump
+     *            (e.g., the compiler phase in which request is made)
+     * @param arguments arguments referenced by the format specifiers in {@code format}
      */
-    default void addCapability(Object capability) {
-    }
+    void dump(DebugContext debug, Object object, String format, Object... arguments);
 
     /**
      * Flushes and releases resources managed by this dump handler. A subsequent call to
-     * {@link #dump(java.lang.Object, java.lang.String, java.lang.Object...)} will create and open
-     * new resources. That is, this method can be used to reset the handler.
+     * {@link #dump} will create and open new resources. That is, this method can be used to reset
+     * the handler.
      */
     @Override
-    void close();
+    default void close() {
+    }
 }