[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..ffce9d24fab527f995e994818660434f66f64205
--- /dev/null
+++ b/chrome/android/java/src/org/chromium/chrome/browser/notifications/ChannelsUpdater.java
@@ -0,0 +1,49 @@
+// 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.annotation.SuppressLint;
+import android.app.NotificationManager;
+import android.content.Context;
+
+import org.chromium.base.BuildInfo;
+import org.chromium.base.ContextUtils;
+
+/**
+ * Contains helper methods for checking if we should update channels and updating them if so.
+ */
+public class ChannelsUpdater {
+    private static final String CHANNELS_VERSION_KEY = "channels_version_key";
+    /**
+     * Version number identifying the current set of channels. This should be incremented whenever

[nyquist, 2017/04/10 21:04:30]

s/should/must/

[awdf, 2017/04/11 14:19:21]

Done.

+     * any channels are added or removed from the set of channels created in
+     * {@link ChannelsInitializer#initializeStartupChannels()}
+     */
+    private static final int CHANNELS_VERSION = 1;

[awdf, 2017/04/11 14:19:21]

I usually count from 0, set to 1 from manual testing. will revert.

+
+    public static boolean shouldUpdateChannels() {
+        return BuildInfo.isAtLeastO()
+                && ContextUtils.getAppSharedPreferences().getInt(CHANNELS_VERSION_KEY, -1)
+                != CHANNELS_VERSION;
+    }
+
+    @SuppressLint("NewApi") // For Context.getSystemService(Class)
+    public static void updateChannels(Context context) {

[nyquist, 2017/04/10 21:04:30]

This seems to be an important part of our future lives... Do we want to make
this class testable? That would probably include the private method taking an
int, etc., and also probably doing some tricks like a LazyHolder to keep the
public API similar. And maybe mock the ChannelsInitializer or something along
those lines?

I don't feel strongly though, it's quite trivial code, but it feels like it
should be tested.

(see here for LazyHolder: 
https://chromium.googlesource.com/chromium/src/+/b87f01f54ba47ace1ddf35476a91...
)

[awdf, 2017/04/11 14:19:21]

The only method that is really testable here is updateChannels, due to the
static calls required in the other two (to BuildInfo & ContextUtils). So I
*could* make a test for updateChannels that checks a mocked channels initializer
has deleteAllChannels & initializeStartupChannels called on it, but given
there's no logic there it feels a bit pointless.

[awdf, 2017/04/11 16:37:03]

On second thoughts, if I just inject the NotificationManagerProxy so we use a
real ChannelsInitializer in the test & check mock notification manager channels
after update are as we expect, I could have a slightly more useful test to check
that ChannelsUpdater + ChannelsInitializer work together correctly.

Think I'll do that.

(Inspired by Peter's unrelated rant about how mocking frameworks ain't as good
as using the real thing)

+        assert BuildInfo.isAtLeastO();
+        ChannelsInitializer channelsInitializer =
+                new ChannelsInitializer(new NotificationManagerProxyImpl(
+                        context.getSystemService(NotificationManager.class)));
+        channelsInitializer.deleteAllChannels();
+        channelsInitializer.initializeStartupChannels();
+        storeChannelVersionInPrefs();
+    }
+
+    private static void storeChannelVersionInPrefs() {
+        ContextUtils.getAppSharedPreferences()
+                .edit()
+                .putInt(CHANNELS_VERSION_KEY, CHANNELS_VERSION)
+                .apply();
+    }
+}