Adds the contextMessage field to notifications.

chrome/browser/extensions/api/notifications/notifications_api.cc

Index: chrome/browser/extensions/api/notifications/notifications_api.cc
diff --git a/chrome/browser/extensions/api/notifications/notifications_api.cc b/chrome/browser/extensions/api/notifications/notifications_api.cc
index 51089fa6443fa4631d80f7a5b43329d4230fdef4..e78798e56482778adcff83e894975c915e66f645 100644
--- a/chrome/browser/extensions/api/notifications/notifications_api.cc
+++ b/chrome/browser/extensions/api/notifications/notifications_api.cc
@@ -284,6 +284,9 @@ bool NotificationsApiFunction::CreateNotification(
           UTF8ToUTF16(*options->expanded_message);
     }
 
+    if (options->context_message)
+      optional_fields.context_message = UTF8ToUTF16(*options->context_message);
+
     bool has_image = NotificationBitmapToGfxImage(options->image_bitmap.get(),
                                                   &optional_fields.image);
     // We should have an image if and only if the type is an image type.
@@ -384,6 +387,9 @@ bool NotificationsApiFunction::UpdateNotification(
       }
     }
 
+    if (options->context_message)
+      notification->set_context_message(UTF8ToUTF16(*options->context_message));
+
     if (options->expanded_message) {
       notification->set_expanded_message(
           UTF8ToUTF16(*options->expanded_message));