[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..bd45fe82d327cda73bdd7ed8c78abd92325aefcd
--- /dev/null
+++ b/chrome/android/java/src/org/chromium/chrome/browser/notifications/ChannelsUpdater.java
@@ -0,0 +1,69 @@
+// 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";
+    /**
+     * Version number identifying the current set of channels. This must be incremented whenever
+     * any channels are added or removed from the set of channels created in
+     * {@link ChannelsInitializer#initializeStartupChannels()}
+     */
+    private static final int CHANNELS_VERSION = 0;
+    private final ChannelsInitializer mChannelsInitializer;

[nyquist, 2017/04/11 19:03:49]

Optional: Extra newline before the non-static members?

[awdf, 2017/04/12 13:58:15]

Done.

+    private final SharedPreferences mSharedPreferences;
+    private boolean mIsAtLeastO;

[nyquist, 2017/04/11 19:03:49]

Nit: final here and mChannelsVersion

[awdf, 2017/04/12 13:58:15]

Done.

+    private int mChannelsVersion;
+
+    public static ChannelsUpdater getInstance() {
+        return LazyHolder.INSTANCE;
+    }
+
+    private static class LazyHolder {
+        public static final ChannelsUpdater INSTANCE = new ChannelsUpdater(BuildInfo.isAtLeastO(),
+                ContextUtils.getAppSharedPreferences(),
+                new NotificationManagerProxyImpl(
+                        (NotificationManager) ContextUtils.getApplicationContext().getSystemService(
+                                Context.NOTIFICATION_SERVICE)),
+                CHANNELS_VERSION);
+    }
+
+    @VisibleForTesting
+    ChannelsUpdater(boolean isAtLeastO, SharedPreferences sharedPreferences,
+            NotificationManagerProxy notificationManagerProxy, int channelsVersion) {
+        mIsAtLeastO = isAtLeastO;
+        mSharedPreferences = sharedPreferences;
+        mChannelsInitializer = new ChannelsInitializer(notificationManagerProxy);
+        mChannelsVersion = channelsVersion;
+    }
+
+    public boolean shouldUpdateChannels() {
+        return mIsAtLeastO
+                && mSharedPreferences.getInt(CHANNELS_VERSION_KEY, -1) != mChannelsVersion;
+    }
+
+    public void updateChannels() {
+        if (!mIsAtLeastO) return;
+        mChannelsInitializer.deleteAllChannels();
+        mChannelsInitializer.initializeStartupChannels();

[Peter Beverloo, 2017/04/11 19:08:29]

This assumes that removing and recreating channels is fine, which may not
necessarily be the case in OEM adoptions of O. Maybe we should add a TODO for
only creating or deleting the channels that need to be modified?

Fine to wait until we can drop the reflection, I don't expect this to be an
issue in M59 in either case.

[awdf, 2017/04/12 13:58:15]

Added a TODO. There's also the risk of a race condition right now, so agree we
should do this soon.

+        storeChannelVersionInPrefs();
+    }
+
+    private void storeChannelVersionInPrefs() {
+        mSharedPreferences.edit().putInt(CHANNELS_VERSION_KEY, mChannelsVersion).apply();
+    }
+}