Handle notification preferences intent from gear icon.

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

Index: chrome/android/java/src/org/chromium/chrome/browser/notifications/NotificationConstants.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/notifications/NotificationConstants.java b/chrome/android/java/src/org/chromium/chrome/browser/notifications/NotificationConstants.java
index b5aa541e6484a8219fb7365bcae380a7f712e143..4243ff3277b3e05a1089a86fa1604cfda407138b 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/notifications/NotificationConstants.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/notifications/NotificationConstants.java
@@ -15,6 +15,7 @@
             "org.chromium.chrome.browser.notifications.CLOSE_NOTIFICATION";
 
     public static final String EXTRA_NOTIFICATION_ID = "notification_id";
+    public static final String EXTRA_NOTIFICATION_TAG = "notification_tag";
 
     // TODO(peter): Remove these extras once Notifications are powered by a database on the
     // native side, that contains all the additional information.
@@ -30,4 +31,9 @@
      * Unique identifier for the "Signed in to Chrome" notification.
      */
     public static final int NOTIFICATION_ID_SIGNED_IN = 2;
+
+    /**
+     * Separator used to concatenate multiple pieces of data into a notification tag.

[Peter Beverloo, 2015/02/24 17:48:02]

Please clarify in this comment that the separator will only be used to separate
the origin from additional content, e.g. the tag. This is important because
origins can't contain semi-colons, where "a piece of data" can.

[Michael van Ouwerkerk, 2015/02/25 18:12:44]

Done.

+     */
+    public static final String NOTIFICATION_TAG_SEPARATOR = ";";
 }