[Autofill Assistant] Add animations when setting carousel chips.

This CL adds animations when carousels chips are changed. When setting
the new list of chips, we compute the minimum set of operations (insert,
delete, substitute) required to transform the old list into the new one
(also known as Levenshtein Distance) and we apply those operations.

Animations themselves are automatically added by the RecyclerView
containing the chips.

Videos:
 - Before: http://go/aa-carousel-before
 - After: http://go/aa-carousel-after

Change-Id: Iaaf78e3a8280fead319dea338bd2a0eb5042aff6
Reviewed-on: https://chromium-review.googlesource.com/c/1491618
Commit-Queue: Jordan Demeulenaere <jdemeulenaere@chromium.org>
Reviewed-by: Stephane Zermatten <szermatt@chromium.org>
Cr-Commit-Position: refs/heads/master@{#636769}

chrome/android/java/src/org/chromium/chrome/browser/autofill_assistant/AutofillAssistantUiController.java

@@ -238,8 +238,14 @@ class AutofillAssistantUiController implements AssistantCoordinator.Delegate {
     }
 
     private void setChips(AssistantCarouselModel model, List<AssistantChip> chips) {
-        model.getChipsModel().set(chips);
         model.set(ALIGNMENT, computeAlignment(chips));
+
+        // We apply the minimum set of operations on the current chips to transform it in the target
+        // list of chips. When testing for chip equivalence, we only compare their type and text but
+        // all substitutions will still be applied so we are sure we display the given {@code chips}
+        // with their associated callbacks.
+        EditDistance.transform(model.getChipsModel(), chips,
+                (a, b) -> a.getType() == b.getType() && a.getText().equals(b.getText()));
     }
 
     @CalledByNative

chrome/android/java/src/org/chromium/chrome/browser/autofill_assistant/carousel/AssistantCarouselCoordinator.java

@@ -9,6 +9,7 @@ import android.graphics.Rect;
 import android.support.annotation.Nullable;
 import android.support.v7.widget.LinearLayoutManager;
 import android.support.v7.widget.RecyclerView;
+import android.support.v7.widget.RecyclerView.ViewHolder;
 import android.util.TypedValue;
 import android.view.View;
 
@@ -36,10 +37,6 @@ public class AssistantCarouselCoordinator {
         mView = new RecyclerView(context);
         mView.setLayoutManager(mLayoutManager);
         mView.addItemDecoration(new SpaceItemDecoration(context));
-        mView.getItemAnimator().setAddDuration(0);
-        mView.getItemAnimator().setChangeDuration(0);
-        mView.getItemAnimator().setMoveDuration(0);
-        mView.getItemAnimator().setRemoveDuration(0);
         mView.setAdapter(new RecyclerViewAdapter<>(
                 new SimpleRecyclerViewMcp<>(model.getChipsModel(), AssistantChip::getType,
                         AssistantChipViewHolder::bind),
@@ -125,7 +122,9 @@ public class AssistantCarouselCoordinator {
         @Override
         public void getItemOffsets(
                 Rect outRect, View view, RecyclerView parent, RecyclerView.State state) {
-            if (mCentered && parent.getAdapter().getItemCount() == 1) {
+            // We use RecyclerView.State#getItemCount() as it returns the correct value when the
+            // carousel is being animated.
+            if (mCentered && state.getItemCount() == 1) {
                 // We have one view and want it horizontally centered. By this time the parent
                 // measured width is correct (as it matches its parent), but we need to explicitly
                 // measure how big the chip view wants to be.
@@ -133,7 +132,7 @@ public class AssistantCarouselCoordinator {
                 view.measure(
                         View.MeasureSpec.makeMeasureSpec(availableWidth, View.MeasureSpec.AT_MOST),
                         View.MeasureSpec.makeMeasureSpec(
-                                parent.getMeasuredHeight(), View.MeasureSpec.AT_MOST));
+                                parent.getMeasuredHeight(), View.MeasureSpec.UNSPECIFIED));
 
                 int margin = (availableWidth - view.getMeasuredWidth()) / 2;
                 outRect.left = margin;
@@ -142,6 +141,18 @@ public class AssistantCarouselCoordinator {
             }
 
             int position = parent.getChildAdapterPosition(view);
+
+            // If old position != NO_POSITION, it means the carousel is being animated and we should
+            // use that position in our logic.
+            ViewHolder viewHolder = parent.getChildViewHolder(view);
+            if (viewHolder != null && viewHolder.getOldPosition() != RecyclerView.NO_POSITION) {
+                position = viewHolder.getOldPosition();
+            }
+
+            if (position == RecyclerView.NO_POSITION) {
+                return;
+            }
+
             int left;
             int right;
             if (position == 0) {
@@ -150,7 +161,7 @@ public class AssistantCarouselCoordinator {
                 left = mInnerSpacePx;
             }
 
-            if (position == parent.getAdapter().getItemCount() - 1) {
+            if (position == state.getItemCount() - 1) {
                 right = mOuterSpacePx;
             } else {
                 right = mInnerSpacePx;

chrome/android/java_sources.gni

@@ -149,6 +149,7 @@ chrome_java_sources = [
   "java/src/org/chromium/chrome/browser/autofill_assistant/AutofillAssistantMetrics.java",
   "java/src/org/chromium/chrome/browser/autofill_assistant/AutofillAssistantPreferencesUtil.java",
   "java/src/org/chromium/chrome/browser/autofill_assistant/AutofillAssistantUiController.java",
+  "java/src/org/chromium/chrome/browser/autofill_assistant/EditDistance.java",
   "java/src/org/chromium/chrome/browser/autofill_assistant/FeedbackContext.java",
   "java/src/org/chromium/chrome/browser/autofill_assistant/carousel/AssistantCarouselCoordinator.java",
   "java/src/org/chromium/chrome/browser/autofill_assistant/carousel/AssistantCarouselModel.java",
@@ -1941,6 +1942,7 @@ chrome_test_java_sources = [
   "javatests/src/org/chromium/chrome/browser/autofill/keyboard_accessory/PasswordAccessorySheetViewTest.java",
   "javatests/src/org/chromium/chrome/browser/autofill/keyboard_accessory/PasswordAccessorySheetModernViewTest.java",
   "javatests/src/org/chromium/chrome/browser/autofill_assistant/AutofillAssistantUiTest.java",
+  "javatests/src/org/chromium/chrome/browser/autofill_assistant/EditDistanceTest.java",
   "javatests/src/org/chromium/chrome/browser/banners/AppBannerManagerTest.java",
   "javatests/src/org/chromium/chrome/browser/bookmarks/BookmarkBridgeTest.java",
   "javatests/src/org/chromium/chrome/browser/bookmarks/BookmarkModelTest.java",

chrome/android/javatests/src/org/chromium/chrome/browser/autofill_assistant/EditDistanceTest.java

+// Copyright 2019 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.autofill_assistant;
+
+import static org.mockito.Mockito.inOrder;
+import static org.mockito.Mockito.verify;
+
+import android.support.test.filters.SmallTest;
+
+import org.junit.Assert;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.JUnit4;
+import org.mockito.InOrder;
+import org.mockito.Mockito;
+import org.mockito.junit.MockitoJUnit;
+import org.mockito.junit.MockitoRule;
+
+import org.chromium.ui.modelutil.ListModel;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+
+/**
+ * Unit test suite for {@link EditDistance}.
+ */
+@RunWith(JUnit4.class)
+public class EditDistanceTest {
+    @Rule
+    public MockitoRule mMockitoRule = MockitoJUnit.rule();
+
+    @Test
+    @SmallTest
+    public void testEmptySource() {
+        ListModel<Integer> spiedListModel = createSpiedListModel();
+        testTransformation(spiedListModel, Arrays.asList(1, 2, 3));
+        InOrder inOrder = inOrder(spiedListModel);
+        inOrder.verify(spiedListModel).add(0, 3);
+        inOrder.verify(spiedListModel).add(0, 2);
+        inOrder.verify(spiedListModel).add(0, 1);
+    }
+
+    @Test
+    @SmallTest
+    public void testEmptyTarget() {
+        ListModel<Integer> spiedListModel = createSpiedListModel(1, 2, 3);
+        testTransformation(spiedListModel, Collections.emptyList());
+        InOrder inOrder = inOrder(spiedListModel);
+        inOrder.verify(spiedListModel).removeAt(2);
+        inOrder.verify(spiedListModel).removeAt(1);
+        inOrder.verify(spiedListModel).removeAt(0);
+    }
+
+    @Test
+    @SmallTest
+    public void testEmptySourceAndEmptyTarget() {
+        testTransformation(createSpiedListModel(), Collections.emptyList());
+    }
+
+    @Test
+    @SmallTest
+    public void testEqualSourceAndTarget() {
+        testTransformation(createSpiedListModel(1, 2, 3), Arrays.asList(1, 2, 3));
+    }
+
+    @Test
+    @SmallTest
+    public void testInsertBeginning() {
+        ListModel<Integer> spiedListModel = createSpiedListModel(2, 3);
+        testTransformation(spiedListModel, Arrays.asList(1, 2, 3));
+        verify(spiedListModel).add(0, 1);
+    }
+
+    @Test
+    @SmallTest
+    public void testInsertMiddle() {
+        ListModel<Integer> spiedListModel = createSpiedListModel(1, 3);
+        testTransformation(spiedListModel, Arrays.asList(1, 2, 3));
+        verify(spiedListModel).add(1, 2);
+    }
+
+    @Test
+    @SmallTest
+    public void testInsertEnd() {
+        ListModel<Integer> spiedListModel = createSpiedListModel(1, 2);
+        testTransformation(spiedListModel, Arrays.asList(1, 2, 3));
+        verify(spiedListModel).add(2, 3);
+    }
+
+    @Test
+    @SmallTest
+    public void testDeleteBeginning() {
+        ListModel<Integer> spiedListModel = createSpiedListModel(1, 2, 3);
+        testTransformation(spiedListModel, Arrays.asList(2, 3));
+        verify(spiedListModel).removeAt(0);
+    }
+
+    @Test
+    @SmallTest
+    public void testDeleteMiddle() {
+        ListModel<Integer> spiedListModel = createSpiedListModel(1, 2, 3);
+        testTransformation(spiedListModel, Arrays.asList(1, 3));
+        verify(spiedListModel).removeAt(1);
+    }
+
+    @Test
+    @SmallTest
+    public void testDeleteEnd() {
+        ListModel<Integer> spiedListModel = createSpiedListModel(1, 2, 3);
+        testTransformation(spiedListModel, Arrays.asList(1, 2));
+        verify(spiedListModel).removeAt(2);
+    }
+
+    @Test
+    @SmallTest
+    public void testSubstitutionBeginning() {
+        ListModel<Integer> spiedListModel = createSpiedListModel(0, 2, 3);
+        testTransformation(spiedListModel, Arrays.asList(1, 2, 3));
+        verify(spiedListModel).update(0, 1);
+    }
+
+    @Test
+    @SmallTest
+    public void testSubstitutionMiddle() {
+        ListModel<Integer> spiedListModel = createSpiedListModel(1, 0, 3);
+        testTransformation(spiedListModel, Arrays.asList(1, 2, 3));
+        verify(spiedListModel).update(1, 2);
+    }
+
+    @Test
+    @SmallTest
+    public void testSubstitutionEnd() {
+        ListModel<Integer> spiedListModel = createSpiedListModel(1, 2, 0);
+        testTransformation(spiedListModel, Arrays.asList(1, 2, 3));
+        verify(spiedListModel).update(2, 3);
+    }
+
+    @Test
+    @SmallTest
+    public void testMultipleInsert() {
+        ListModel<Integer> spiedListModel = createSpiedListModel(3, 6);
+        testTransformation(spiedListModel, Arrays.asList(1, 2, 3, 4, 5, 6, 7, 8));
+        InOrder inOrder = inOrder(spiedListModel);
+        inOrder.verify(spiedListModel).add(2, 8);
+        inOrder.verify(spiedListModel).add(2, 7);
+        inOrder.verify(spiedListModel).add(1, 5);
+        inOrder.verify(spiedListModel).add(1, 4);
+        inOrder.verify(spiedListModel).add(0, 2);
+        inOrder.verify(spiedListModel).add(0, 1);
+    }
+
+    @Test
+    @SmallTest
+    public void testMultipleDelete() {
+        ListModel<Integer> spiedListModel = createSpiedListModel(1, 2, 3, 4, 5, 6, 7, 8);
+        testTransformation(spiedListModel, Arrays.asList(3, 6));
+        InOrder inOrder = inOrder(spiedListModel);
+        inOrder.verify(spiedListModel).removeAt(7);
+        inOrder.verify(spiedListModel).removeAt(6);
+        inOrder.verify(spiedListModel).removeAt(4);
+        inOrder.verify(spiedListModel).removeAt(3);
+        inOrder.verify(spiedListModel).removeAt(1);
+        inOrder.verify(spiedListModel).removeAt(0);
+    }
+
+    @Test
+    @SmallTest
+    public void testMultipleSubstitutions() {
+        ListModel<Integer> spiedListModel = createSpiedListModel(0, 0, 3, 0, 0, 6, 0, 0);
+        testTransformation(spiedListModel, Arrays.asList(1, 2, 3, 4, 5, 6, 7, 8));
+        verify(spiedListModel).update(0, 1);
+        verify(spiedListModel).update(1, 2);
+        verify(spiedListModel).update(3, 4);
+        verify(spiedListModel).update(4, 5);
+        verify(spiedListModel).update(6, 7);
+        verify(spiedListModel).update(7, 8);
+    }
+
+    @Test
+    @SmallTest
+    public void testPopAndAppend() {
+        ListModel<Integer> spiedListModel = createSpiedListModel(1, 2, 3);
+        testTransformation(spiedListModel, Arrays.asList(2, 3, 4));
+        InOrder inOrder = inOrder(spiedListModel);
+        inOrder.verify(spiedListModel).add(3, 4);
+        inOrder.verify(spiedListModel).removeAt(0);
+    }
+
+    @Test
+    @SmallTest
+    public void testAppendAndPop() {
+        ListModel<Integer> spiedListModel = createSpiedListModel(1, 2, 3);
+        testTransformation(spiedListModel, Arrays.asList(0, 1, 2));
+        InOrder inOrder = inOrder(spiedListModel);
+        inOrder.verify(spiedListModel).removeAt(2);
+        inOrder.verify(spiedListModel).add(0, 0);
+    }
+
+    @Test
+    @SmallTest
+    public void testMixedOperations() {
+        ListModel<Integer> spiedListModel = createSpiedListModel(1, 2, 3, 4, 5, 6);
+        testTransformation(spiedListModel, Arrays.asList(2, 8, 4, 5, 7, 6));
+
+        // 0-cost substitutions.
+        verify(spiedListModel).update(1, 2);
+        verify(spiedListModel).update(3, 4);
+        verify(spiedListModel).update(4, 5);
+        verify(spiedListModel).update(5, 6);
+
+        verify(spiedListModel).update(2, 8);
+        InOrder inOrder = inOrder(spiedListModel);
+        inOrder.verify(spiedListModel).add(5, 7);
+        inOrder.verify(spiedListModel).removeAt(0);
+    }
+
+    private void testTransformation(ListModel<Integer> source, List<Integer> target) {
+        EditDistance.transform(source, target, Integer::equals);
+
+        List<Integer> sourceList = new ArrayList<>();
+        for (Integer value : source) {
+            sourceList.add(value);
+        }
+        Assert.assertEquals(target, sourceList);
+    }
+
+    private static ListModel<Integer> createSpiedListModel(Integer... values) {
+        ListModel<Integer> model = new ListModel<>();
+        model.set(values);
+        return Mockito.spy(model);
+    }
+}