Upstream base implementations of TabModel, TabModelSelector, and TabModelObserver.

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

Index: chrome/android/java/src/org/chromium/chrome/browser/tabmodel/TabModelDelegate.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/tabmodel/TabModelDelegate.java b/chrome/android/java/src/org/chromium/chrome/browser/tabmodel/TabModelDelegate.java
new file mode 100644
index 0000000000000000000000000000000000000000..9b8c8a7ba779d250eb5c132bd876fff1307f0239
--- /dev/null
+++ b/chrome/android/java/src/org/chromium/chrome/browser/tabmodel/TabModelDelegate.java
@@ -0,0 +1,39 @@
+// 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.TabSelectionType;
+
+/**
+ * This class serves as a callback from TabModel to TabModelSelector. The number of methods in this
+ * class should be reduced to a minimum. http://crbug.com/263579
+ */
+public interface TabModelDelegate {
+
+    /**
+     * Called when a new tab is created.
+     */
+    void didCreateNewTab(Tab tab);
+
+    /**
+     * Called when the {@link TabModelSelector} or its {@link TabModel} has changed.
+     */
+    void didChange();
+
+    /**
+     * Requests the specified to be shown.
+     * @param tab The tab that is requested to be shown.
+     * @param type The reason why this tab was requested to be shown.
+     */
+    void requestToShowTab(Tab tab, TabSelectionType type);
+
+    // TODO(aurimas): clean these methods up.
+    TabModel getCurrentModel();
+    TabModel getModel(boolean incognito);
+    boolean isInOverviewMode();
+    boolean isSessionRestoreInProgress();
+    void selectModel(boolean incognito);
+}