Upstream oodles of Chrome for Android code into Chromium.

chrome/android/java_staging/src/org/chromium/chrome/browser/compositor/overlays/strip/StripStacker.java

+// Copyright 2015 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.compositor.overlays.strip;
+
+import org.chromium.chrome.browser.compositor.layouts.Layout;
+
+/**
+ * An interface that defines how to stack tabs and how they should look visually.  This lets
+ * certain components customize how the {@link StripLayoutHelper} functions and how other
+ * {@link Layout}s visually order tabs.
+ */
+public interface StripStacker {
+    /**
+     * @return Whether or not the close button can be shown.  Note that even if it can be shown,
+     *         it might not be due to how much of the tab is actually visible to preserve proper hit
+     *         target sizes.
+     */
+    public boolean canShowCloseButton();
+
+    /**
+     * @return Whether or not the title text can slide to the right to stay visible.
+     */
+    public boolean canSlideTitleText();
+
+    /**
+     * This gives the implementing class a chance to determine how the tabs should be ordered
+     * visually.  The positioning logic is the same regardless, this just has to do with visual
+     * stacking.
+     *
+     * @param selectedIndex The selected index of the tabs.
+     * @param indexOrderedTabs A list of tabs ordered by index.
+     * @param outVisualOrderedTabs The new list of tabs, ordered from back to front visually.
+     */
+    public void createVisualOrdering(int selectedIndex, StripLayoutTab[] indexOrderedTabs,
+            StripLayoutTab[] outVisualOrderedTabs);
+
+    /**
+     * Performs an occlusion pass, setting the visibility on tabs depending on whether or not they
+     * overlap each other perfectly.  This is relegated to this interface because the implementing
+     * class knows the proper visual order to optimize this pass.
+     * @param selectedIndex The selected index of the tabs.
+     * @param indexOrderedTabs A list of tabs ordered by index.
+     */
+    public void performOcclusionPass(int selectedIndex, StripLayoutTab[] indexOrderedTabs);
+}