Upstream base implementations of TabModel, TabModelSelector, and TabModelObserver.

chrome/android/java/src/org/chromium/chrome/browser/tabmodel/EmptyTabModelObserver.java

Index: chrome/android/java/src/org/chromium/chrome/browser/tabmodel/EmptyTabModelObserver.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/tabmodel/EmptyTabModelObserver.java b/chrome/android/java/src/org/chromium/chrome/browser/tabmodel/EmptyTabModelObserver.java
new file mode 100644
index 0000000000000000000000000000000000000000..648e3528decf7ac3d7b3ce6749618ec380c041a0
--- /dev/null
+++ b/chrome/android/java/src/org/chromium/chrome/browser/tabmodel/EmptyTabModelObserver.java
@@ -0,0 +1,52 @@
+// Copyright 2014 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.chrome.browser.tabmodel;
+
+import org.chromium.chrome.browser.Tab;
+import org.chromium.chrome.browser.tabmodel.TabModel.TabLaunchType;
+import org.chromium.chrome.browser.tabmodel.TabModel.TabSelectionType;
+
+/**
+ * An empty base implementation of the TabModelObserver interface.
+ */
+public class EmptyTabModelObserver implements TabModelObserver {
+
+    @Override
+    public void didSelectTab(Tab tab, TabSelectionType type, int lastId) {
+    }
+
+    @Override
+    public void willCloseTab(Tab tab, boolean animate) {
+    }
+
+    @Override
+    public void didCloseTab(Tab tab) {
+    }
+
+    @Override
+    public void willAddTab(Tab tab, TabLaunchType type) {
+    }
+
+    @Override
+    public void didAddTab(Tab tab, TabLaunchType type) {
+    }
+
+    @Override
+    public void didMoveTab(Tab tab, int newIndex, int curIndex) {
+    }
+
+    @Override
+    public void tabPendingClosure(Tab tab) {
+    }
+
+    @Override
+    public void tabClosureUndone(Tab tab) {
+    }
+
+    @Override
+    public void tabClosureCommitted(Tab tab) {
+    }
+
+}