[Android] Introduce DateDividedAdapter to Chrome

This CL brings DateDividedAdapter to Chrome, and lets Download Manager
UI to utilize it. This adapter will take a list of timed items, groups
these items by date, and displays the groups in sections.

BUG=616324

Review-Url: https://codereview.chromium.org/2154063003
Cr-Commit-Position: refs/heads/master@{#406641}

chrome/android/java/res/layout/download_date_view.xml

+<?xml version="1.0" encoding="utf-8"?>
+<!-- Copyright 2016 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. -->
+
+<TextView xmlns:android="http://schemas.android.com/apk/res/android"
+    style="@style/RobotoMediumStyle"
+    android:layout_width="match_parent"
+    android:layout_height="wrap_content"
+    android:layout_marginBottom="16dp"
+    android:layout_marginEnd="16dp"
+    android:layout_marginStart="16dp"
+    android:layout_marginTop="16dp"
+    android:textSize="16sp" />

chrome/android/java/res/values-v17/styles.xml

@@ -553,6 +553,11 @@
         <item name="android:paddingEnd">16dp</item>
         <item name="android:background">?attr/listChoiceBackgroundIndicator</item>
     </style>
+    <style name="RobotoMediumStyle">
+        <item name="android:fontFamily">sans-serif</item>
+        <item name="android:textStyle">bold</item>
+    </style>
+
     <!-- New tab page RecyclerView overscroll color -->
     <style name="NewTabPageRecyclerView">
         <item name="android:colorEdgeEffect">@color/google_grey_300</item>

chrome/android/java/res/values-v21/styles.xml

@@ -4,6 +4,9 @@
      found in the LICENSE file. -->
 
 <resources>
+    <style name="RobotoMediumStyle">
+        <item name="android:fontFamily">sans-serif-medium</item>
+    </style>
     <!-- Preferences -->
     <style name="PreferencesTheme" parent="ThemeWithActionBar">
         <item name="android:textColorLink">@color/pref_accent_color</item>

chrome/android/java/src/org/chromium/chrome/browser/download/DownloadItem.java

@@ -4,11 +4,13 @@
 
 package org.chromium.chrome.browser.download;
 
+import org.chromium.chrome.browser.widget.DateDividedAdapter.TimedItem;
+
 /**
  * A generic class representing a download item. The item can be either downloaded through the
  * Android DownloadManager, or through Chrome's network stack
  */
-public class DownloadItem {
+public class DownloadItem implements TimedItem {
     static final long INVALID_DOWNLOAD_ID = -1L;
     private boolean mUseAndroidDownloadManager;
     private DownloadInfo mDownloadInfo;
@@ -83,6 +85,7 @@ public class DownloadItem {
      *
      * @return Download start time from System.currentTimeMillis().
      */
+    @Override
     public long getStartTime() {
         return mStartTime;
     }

chrome/android/java/src/org/chromium/chrome/browser/download/ui/DownloadHistoryAdapter.java

@@ -6,6 +6,7 @@ package org.chromium.chrome.browser.download.ui;
 
 import android.content.Context;
 import android.support.v7.widget.RecyclerView;
+import android.support.v7.widget.RecyclerView.ViewHolder;
 import android.text.TextUtils;
 import android.text.format.Formatter;
 import android.view.LayoutInflater;
@@ -17,22 +18,21 @@ import android.widget.TextView;
 import org.chromium.chrome.R;
 import org.chromium.chrome.browser.download.DownloadItem;
 import org.chromium.chrome.browser.util.UrlUtilities;
+import org.chromium.chrome.browser.widget.DateDividedAdapter;
 
-import java.util.ArrayList;
 import java.util.List;
 
 /** Bridges the user's download history and the UI used to display it. */
-public class DownloadHistoryAdapter
-        extends RecyclerView.Adapter<DownloadHistoryAdapter.ViewHolder> {
+public class DownloadHistoryAdapter extends DateDividedAdapter {
 
     /** Holds onto a View that displays information about a downloaded file. */
-    static class ViewHolder extends RecyclerView.ViewHolder {
+    static class ItemViewHolder extends RecyclerView.ViewHolder {
         public ImageView mIconView;
         public TextView mFilenameView;
         public TextView mHostnameView;
         public TextView mFilesizeView;
 
-        public ViewHolder(View itemView) {
+        public ItemViewHolder(View itemView) {
             super(itemView);
             mIconView = (ImageView) itemView.findViewById(R.id.icon_view);
             mFilenameView = (TextView) itemView.findViewById(R.id.filename_view);
@@ -53,27 +53,28 @@ public class DownloadHistoryAdapter
     private static final String MIMETYPE_IMAGE = "image";
     private static final String MIMETYPE_DOCUMENT = "text";
 
-    private final List<DownloadItem> mDownloadItems = new ArrayList<>();
-
     /** Called when the user's download history has been gathered into a List of DownloadItems. */
     public void onAllDownloadsRetrieved(List<DownloadItem> list) {
-        mDownloadItems.clear();
-        for (DownloadItem item : list) mDownloadItems.add(item);
-        notifyDataSetChanged();
+        loadItems(list);
     }
 
     @Override
-    public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
+    protected int getTimedItemViewResId() {
+        return R.layout.download_date_view;
+    }
+
+    @Override
+    public ViewHolder createViewHolder(ViewGroup parent) {
         View v = LayoutInflater.from(parent.getContext()).inflate(
                 R.layout.download_item_view, parent, false);
-        return new ViewHolder(v);
+        return new ItemViewHolder(v);
     }
 
     @Override
-    public void onBindViewHolder(ViewHolder holder, int position) {
+    public void bindViewHolderForTimedItem(ViewHolder current, TimedItem timedItem) {
+        ItemViewHolder holder = (ItemViewHolder) current;
         Context context = holder.mFilesizeView.getContext();
-
-        DownloadItem item = mDownloadItems.get(position);
+        DownloadItem item = (DownloadItem) timedItem;
         holder.mFilenameView.setText(item.getDownloadInfo().getFileName());
         holder.mHostnameView.setText(
                 UrlUtilities.formatUrlForSecurityDisplay(item.getDownloadInfo().getUrl(), false));
@@ -105,16 +106,6 @@ public class DownloadHistoryAdapter
         holder.mIconView.setImageResource(iconResource);
     }
 
-    @Override
-    public int getItemCount() {
-        return mDownloadItems.size();
-    }
-
-    /** Clears out all of the downloads tracked by the Adapter. */
-    public void clear() {
-        mDownloadItems.clear();
-    }
-
     /** Identifies the type of file represented by the given MIME type string. */
     private static int convertMimeTypeToFileType(String mimeType) {
         if (TextUtils.isEmpty(mimeType)) return FILETYPE_OTHER;

chrome/android/java/strings/android_chrome_strings.grd

@@ -189,6 +189,12 @@ CHAR-LIMIT guidelines:
       <message name="IDS_HELP" desc="Generic label for a button that displays help for the current screen.">
         Help
       </message>
+      <message name="IDS_TODAY" desc="Generic Label saying the date is today.">
+        Today
+      </message>
+      <message name="IDS_YESTERDAY" desc="Generic Label saying the date is yesterday.">
+        Yesterday
+      </message>
 
       <!-- Main Preferences -->
       <message name="IDS_PREFERENCES" desc="Title for Chrome's Settings.">

chrome/android/java_sources.gni

@@ -956,6 +956,7 @@ chrome_java_sources = [
   "java/src/org/chromium/chrome/browser/widget/ClipDrawableProgressBar.java",
   "java/src/org/chromium/chrome/browser/widget/CompatibilityTextInputLayout.java",
   "java/src/org/chromium/chrome/browser/widget/ControlContainer.java",
+  "java/src/org/chromium/chrome/browser/widget/DateDividedAdapter.java",
   "java/src/org/chromium/chrome/browser/widget/DualControlLayout.java",
   "java/src/org/chromium/chrome/browser/widget/EmptyAlertEditText.java",
   "java/src/org/chromium/chrome/browser/widget/FadingShadow.java",