[Android] Refactor our notification channel definitions

chrome/android/java/src/org/chromium/chrome/browser/notifications/channels/Channel.java

Index: chrome/android/java/src/org/chromium/chrome/browser/notifications/channels/Channel.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/notifications/channels/Channel.java b/chrome/android/java/src/org/chromium/chrome/browser/notifications/channels/Channel.java
new file mode 100644
index 0000000000000000000000000000000000000000..63d0c8cc089d09b7657b990dbe8cd37a7ddd7b9d
--- /dev/null
+++ b/chrome/android/java/src/org/chromium/chrome/browser/notifications/channels/Channel.java
@@ -0,0 +1,41 @@
+// 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.channels;
+
+/**
+ * Helper class that corresponds to the Android NotificationChannel class,
+ * which we cannot use directly until our compileSdkVersion is bumped to O.
+ *
+ * Only the methods & properties we use have been added, others may be added if the need arises.
+ */
+public class Channel {
+    private final String mId;
+    private final CharSequence mName;
+    private final int mImportance;
+    private final String mGroupId;
+
+    public Channel(String id, CharSequence name, int importance, String groupId) {
+        mId = id;
+        mName = name;
+        mImportance = importance;
+        mGroupId = groupId;
+    }
+
+    public String getId() {
+        return mId;
+    }
+
+    public CharSequence getName() {
+        return mName;
+    }
+
+    public int getImportance() {
+        return mImportance;
+    }
+
+    public String getGroupId() {
+        return mGroupId;
+    }
+}