Java versions of BlimpContents[,Observer] and BlimpNavigationController

blimp/client/core/public/android/java/src/org/chromium/blimp/core_public/EmptyBlimpContentsObserver.java

Index: blimp/client/core/public/android/java/src/org/chromium/blimp/core_public/EmptyBlimpContentsObserver.java
diff --git a/blimp/client/core/public/android/java/src/org/chromium/blimp/core_public/EmptyBlimpContentsObserver.java b/blimp/client/core/public/android/java/src/org/chromium/blimp/core_public/EmptyBlimpContentsObserver.java
new file mode 100644
index 0000000000000000000000000000000000000000..2f4097b2ad633142b6985d81dfbbd839db2f4f42
--- /dev/null
+++ b/blimp/client/core/public/android/java/src/org/chromium/blimp/core_public/EmptyBlimpContentsObserver.java
@@ -0,0 +1,15 @@
+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package org.chromium.blimp.core_public;
+
+/**
+ * EmptyBlimpContentsObserver is a helper class that has an empty implementation of all the
+ * methods in the {@link BlimpContentsObserver}. It is intented to be used by every class that
+ * does not need to implement all the observer-methods.
+ */
+public class EmptyBlimpContentsObserver implements BlimpContentsObserver {
+    @Override
+    public void onUrlUpdated(String url) {}
+}