Upstream oodles of Chrome for Android code into Chromium.

chrome/android/java_staging/src/org/chromium/chrome/browser/compositor/layouts/phone/stack/StackViewAnimation.java

Index: chrome/android/java_staging/src/org/chromium/chrome/browser/compositor/layouts/phone/stack/StackViewAnimation.java
diff --git a/chrome/android/java_staging/src/org/chromium/chrome/browser/compositor/layouts/phone/stack/StackViewAnimation.java b/chrome/android/java_staging/src/org/chromium/chrome/browser/compositor/layouts/phone/stack/StackViewAnimation.java
new file mode 100644
index 0000000000000000000000000000000000000000..60a746e2b1ffdeaea9e0121ea3e200d0fcef6431
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+++ b/chrome/android/java_staging/src/org/chromium/chrome/browser/compositor/layouts/phone/stack/StackViewAnimation.java
@@ -0,0 +1,108 @@
+// 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.layouts.phone.stack;
+
+import android.animation.AnimatorSet;
+import android.animation.ObjectAnimator;
+import android.view.View;
+import android.view.ViewGroup;
+import android.view.ViewGroup.LayoutParams;
+import android.widget.FrameLayout;
+
+import org.chromium.chrome.browser.Tab;
+import org.chromium.chrome.browser.compositor.layouts.phone.stack.StackAnimation.OverviewAnimationType;
+import org.chromium.chrome.browser.tabmodel.TabModel;
+import org.chromium.ui.base.LocalizationUtils;
+import org.chromium.ui.interpolators.BakedBezierInterpolator;
+
+/**
+ * A factory that builds Android view animations for the tab stack.
+ */
+public class StackViewAnimation {
+    private static final int TAB_OPENED_ANIMATION_DURATION = 300;
+    private static final float TAB_OPENED_PIVOT_INSET_DP = 24.f;
+
+    private final float mDpToPx;
+    private final float mWidthDp;
+
+    /**
+     * Constructor.
+     * NOTE: Pass in height and heightMinusTopControls if they're ever needed.
+     *
+     * @param dpToPx                   The density of the device.
+     * @param widthDp                  The width of the layout in dp.
+     */
+    public StackViewAnimation(float dpToPx, float widthDp) {
+        mDpToPx = dpToPx;
+        mWidthDp = widthDp;
+    }
+
+    /**
+     * The wrapper method responsible for delegating animation requests to the appropriate helper
+     * method.
+     * @param type       The type of animation to be created.  This is what determines which helper
+     *                   method is called.
+     * @param tabs       The tabs that make up the current stack.
+     * @param container  The {@link ViewGroup} that {@link View}s can be added to/removed from.
+     * @param model      The {@link TabModel} that this animation will influence.
+     * @param focusIndex The index of the tab that is the focus of this animation.
+     * @return           The resulting {@link AnimatorSet} that will animate the Android views.
+     */
+    public AnimatorSet createAnimatorSetForType(OverviewAnimationType type, StackTab[] tabs,
+            ViewGroup container, TabModel model, int focusIndex) {
+        AnimatorSet set = null;
+
+        if (model != null) {
+            switch (type) {
+                case NEW_TAB_OPENED:
+                    set = createNewTabOpenedAnimatorSet(tabs, container, model, focusIndex);
+                    break;
+                default:
+                    break;
+            }
+        }
+
+        return set;
+    }
+
+    private AnimatorSet createNewTabOpenedAnimatorSet(
+            StackTab[] tabs, ViewGroup container, TabModel model, int focusIndex) {
+        Tab tab = model.getTabAt(focusIndex);
+        if (tab == null || !tab.isNativePage()) return null;
+
+        View view = tab.getView();
+        if (view == null) return null;
+
+        // Set up the view hierarchy
+        if (view.getParent() != null) ((ViewGroup) view.getParent()).removeView(view);
+        ViewGroup bgView = new FrameLayout(view.getContext());
+        bgView.setBackgroundColor(tab.getBackgroundColor());
+        bgView.addView(view);
+        container.addView(
+                bgView, new LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT));
+
+        // Update any compositor state that needs to change
+        if (tabs != null && focusIndex >= 0 && focusIndex < tabs.length) {
+            tabs[focusIndex].setAlpha(0.f);
+        }
+
+        // Build the view animations
+        ObjectAnimator xScale = ObjectAnimator.ofFloat(bgView, View.SCALE_X, 0.f, 1.f);
+        ObjectAnimator yScale = ObjectAnimator.ofFloat(bgView, View.SCALE_Y, 0.f, 1.f);
+        ObjectAnimator alpha = ObjectAnimator.ofFloat(bgView, View.ALPHA, 0.f, 1.f);
+
+        AnimatorSet set = new AnimatorSet();
+        set.playTogether(xScale, yScale, alpha);
+
+        set.setDuration(TAB_OPENED_ANIMATION_DURATION);
+        set.setInterpolator(BakedBezierInterpolator.TRANSFORM_FOLLOW_THROUGH_CURVE);
+
+        float insetPx = TAB_OPENED_PIVOT_INSET_DP * mDpToPx;
+
+        bgView.setPivotY(TAB_OPENED_PIVOT_INSET_DP);
+        bgView.setPivotX(LocalizationUtils.isLayoutRtl() ? mWidthDp * mDpToPx - insetPx : insetPx);
+        return set;
+    }
+}