[Android O] Initialize channels on first launch/upgrade

chrome/android/java/src/org/chromium/chrome/browser/notifications/ChannelsUpdater.java

Index: chrome/android/java/src/org/chromium/chrome/browser/notifications/ChannelsUpdater.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/notifications/ChannelsUpdater.java b/chrome/android/java/src/org/chromium/chrome/browser/notifications/ChannelsUpdater.java
new file mode 100644
index 0000000000000000000000000000000000000000..126d03e66d1917d7e4c187fbcf08daceb3443434
--- /dev/null
+++ b/chrome/android/java/src/org/chromium/chrome/browser/notifications/ChannelsUpdater.java
@@ -0,0 +1,70 @@
+// 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.notifications;
+
+import android.app.NotificationManager;
+import android.content.Context;
+import android.content.SharedPreferences;
+
+import org.chromium.base.BuildInfo;
+import org.chromium.base.ContextUtils;
+import org.chromium.base.VisibleForTesting;
+
+/**
+ * Contains helper methods for checking if we should update channels and updating them if so.
+ */
+public class ChannelsUpdater {
+    @VisibleForTesting
+    static final String CHANNELS_VERSION_KEY = "channels_version_key";
+
+    private final ChannelsInitializer mChannelsInitializer;
+    private final SharedPreferences mSharedPreferences;
+    private final boolean mIsAtLeastO;
+    private final int mChannelsVersion;
+
+    public static ChannelsUpdater getInstance() {
+        return LazyHolder.INSTANCE;
+    }
+
+    private static class LazyHolder {
+        // If pre-O, initialize with nulls as a small optimization to avoid getting AppContext etc
+        // when we won't need it. It's ok for these parameters to be null when mIsAtLeastO is false.
+        public static final ChannelsUpdater INSTANCE = !BuildInfo.isAtLeastO()
+                ? new ChannelsUpdater(false /* isAtLeastO */, null, null, -1)
+                : new ChannelsUpdater(true /* isAtLeastO */, ContextUtils.getAppSharedPreferences(),
+                          new ChannelsInitializer(new NotificationManagerProxyImpl(
+                                  (NotificationManager) ContextUtils.getApplicationContext()
+                                          .getSystemService(Context.NOTIFICATION_SERVICE))),
+                          ChannelsInitializer.CHANNELS_VERSION);
+    }
+
+    @VisibleForTesting
+    ChannelsUpdater(boolean isAtLeastO, SharedPreferences sharedPreferences,
+            ChannelsInitializer channelsInitializer, int channelsVersion) {
+        mIsAtLeastO = isAtLeastO;
+        mSharedPreferences = sharedPreferences;
+        mChannelsInitializer = channelsInitializer;
+        mChannelsVersion = channelsVersion;
+    }
+
+    public boolean shouldUpdateChannels() {
+        return mIsAtLeastO
+                && mSharedPreferences.getInt(CHANNELS_VERSION_KEY, -1) != mChannelsVersion;
+    }
+
+    public void updateChannels() {
+        if (!mIsAtLeastO) return;
+        assert mChannelsInitializer != null;
+        // TODO(crbug.com/710843) Iterate through existing channels instead of deleting them all.
+        mChannelsInitializer.deleteAllChannels();
+        mChannelsInitializer.initializeStartupChannels();
+        storeChannelVersionInPrefs();
+    }
+
+    private void storeChannelVersionInPrefs() {
+        assert mSharedPreferences != null;
+        mSharedPreferences.edit().putInt(CHANNELS_VERSION_KEY, mChannelsVersion).apply();
+    }
+}