[Android O] Split out browser notification channels

chrome/android/java/strings/android_chrome_strings.grd

 <?xml version="1.0" encoding="UTF-8"?>
 
 <!-- android_chrome_strings.grd contains strings for Chrome for Android.
 
 FAQ:
   - How do I add, change, or remove a string?
       Just update this file.
   - Translations will happen automatically??
       Yes, indeed. Just add your string before the branch point and
       make the description good.
@@ skipping 232 matching lines @@
       </message>
       <message name="IDS_PREFS_SECTION_ADVANCED" desc='Title of "Advanced" section of preferences. [CHAR-LIMIT=32]'>
         Advanced
       </message>
       <message name="IDS_ENTER_VR" desc="Menu item for entering VR. [CHAR-LIMIT=27]">
         Enter VR
       </message>
       <message name="IDS_NOTIFICATION_CATEGORY_GROUP_GENERAL" desc='Subheading for "General" section of a list of notification categories. [CHAR-LIMIT=32]'>
         General
       </message>
+      <message name="IDS_NOTIFICATION_CATEGORY_INCOGNITO" desc="Label for notification that indicates incognito mode is active, within a list of notification categories. [CHAR-LIMIT=32]">
+        Incognito
+      </message>
+      <message name="IDS_NOTIFICATION_CATEGORY_MEDIA" desc="Label for notifications shown when media is playing or recording, within a list of notification categories. [CHAR-LIMIT=32]">
+        Media
+      </message>
+      <message name="IDS_NOTIFICATION_CATEGORY_DOWNLOADS" desc="Label for notifications shown when something is downloading, within a list of notification categories. [CHAR-LIMIT=32]">
+        Downloads
+      </message>
       <message name="IDS_NOTIFICATION_CATEGORY_BROWSER" desc="Label for browser-related notifications, within a list of notification categories. [CHAR-LIMIT=32]">
         Browser
       </message>
       <message name="IDS_NOTIFICATION_CATEGORY_SITES" desc="Label for notifications from websites, within a list of notification categories. [CHAR-LIMIT=32]">
         Sites
       </message>
 
       <!-- Sign-in preference -->
       <message name="IDS_SIGN_IN_TO_CHROME" desc="Title for the button to sign in to Chrome using one's Google account. [CHAR-LIMIT=27]">
         Sign in to Chrome
@@ skipping 2657 matching lines @@
         Search with <ph name="PRODUCT_NAME">%1$s<ex>Google</ex></ph>
       </message>
 
       <!-- Launcher Shortcuts -->
       <message name="IDS_DISABLED_INCOGNITO_LAUNCHER_SHORTCUT_MESSAGE" desc="Text for a toast displayed prompting the user to remove the disabled 'New incognito tab' app shortcut and recreate it.">
         Remove and recreate this shortcut
       </message>
     </messages>
   </release>
 </grit>