🍝🏠 Refactor MostVisited UI management, extract it for reuse in Home.

chrome/android/java/src/org/chromium/chrome/browser/suggestions/TileGrid.java

Index: chrome/android/java/src/org/chromium/chrome/browser/suggestions/TileGrid.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/suggestions/TileGrid.java b/chrome/android/java/src/org/chromium/chrome/browser/suggestions/TileGrid.java
new file mode 100644
index 0000000000000000000000000000000000000000..1ed212213b6a63f58cefa578367c707d9045161b
--- /dev/null
+++ b/chrome/android/java/src/org/chromium/chrome/browser/suggestions/TileGrid.java
@@ -0,0 +1,110 @@
+// Copyright 2017 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.suggestions;
+
+import android.view.LayoutInflater;
+import android.view.ViewGroup;
+
+import org.chromium.chrome.R;
+import org.chromium.chrome.browser.ntp.ContextMenuManager;
+import org.chromium.chrome.browser.ntp.MostVisitedLayout;
+import org.chromium.chrome.browser.ntp.cards.ItemViewType;
+import org.chromium.chrome.browser.ntp.cards.NewTabPageViewHolder;
+import org.chromium.chrome.browser.ntp.cards.OptionalLeaf;
+
+/**
+ * The model and controller for a group of site suggestion tiles that will be rendered in a grid.
+ */
+public class TileGrid extends OptionalLeaf implements TileGroup.Observer {
+    private static final int MAX_TILES = 4;
+    private static final int MAX_ROWS = 1;
+
+    private final TileGroup mTileGroup;
+
+    public TileGrid(SuggestionsUiDelegate uiDelegate, ContextMenuManager contextMenuManager,
+            TileGroup.Delegate tileGroupDelegate) {
+        mTileGroup = new TileGroup(
+                uiDelegate, contextMenuManager, tileGroupDelegate, /* observer = */ this);
+        mTileGroup.startObserving(MAX_TILES);
+    }
+
+    @Override
+    @ItemViewType
+    protected int getItemViewType() {
+        return ItemViewType.TILE_GRID;
+    }
+
+    @Override
+    protected void onBindViewHolder(NewTabPageViewHolder holder) {
+        assert holder instanceof ViewHolder;
+        ((ViewHolder) holder).onBindViewHolder(mTileGroup);
+    }
+
+    @Override
+    public void onInitialTileDataLoaded() {
+        onTileDataChanged();
+    }
+
+    @Override
+    public void onTileDataChanged() {
+        notifyItemChanged(0);
+        setVisible(mTileGroup.getTiles().length != 0);
+    }
+
+    @Override
+    public void onTileCountChanged() {
+        onTileDataChanged();
+    }
+
+    @Override
+    public void onTileIconChanged(Tile tile) {
+        notifyItemChanged(0, new ViewHolder.UpdateIconViewCallback(tile));
+    }
+
+    @Override
+    public void onLoadTaskAdded() {}
+
+    @Override
+    public void onLoadTaskCompleted() {}
+
+    /**
+     * The {@code ViewHolder} for the {@link TileGrid}.
+     */
+    public static class ViewHolder extends NewTabPageViewHolder {
+        private final MostVisitedLayout mLayout;
+
+        public ViewHolder(ViewGroup parentView) {
+            super(LayoutInflater.from(parentView.getContext())
+                            .inflate(R.layout.suggestions_site_tile_grid, parentView, false));
+            mLayout = (MostVisitedLayout) itemView;
+        }
+
+        public void onBindViewHolder(TileGroup tileGroup) {
+            mLayout.setMaxRows(MAX_ROWS);
+            tileGroup.renderTileViews(mLayout, /* trackLoadTasks = */ false);
+        }
+
+        public void updateIconView(Tile tile) {
+            mLayout.updateIconView(tile.getUrl(), tile.getIcon());
+        }
+
+        /**
+         * Callback to update the icon view for the view holder.
+         */
+        public static class UpdateIconViewCallback extends PartialBindCallback {
+            private final Tile mTile;
+
+            public UpdateIconViewCallback(Tile tile) {
+                mTile = tile;
+            }
+
+            @Override
+            public void onResult(NewTabPageViewHolder holder) {
+                assert holder instanceof ViewHolder;
+                ((ViewHolder) holder).updateIconView(mTile);
+            }
+        }
+    }
+}