Allow partial update for notification update API

chrome/renderer/resources/extensions/notifications_custom_bindings.js

Index: chrome/renderer/resources/extensions/notifications_custom_bindings.js
diff --git a/chrome/renderer/resources/extensions/notifications_custom_bindings.js b/chrome/renderer/resources/extensions/notifications_custom_bindings.js
index 5150a4fb1e4b1a8ee3d7a63f052b9e1394c4e216..e56a98bdd37800376a0c970c71b76bd08c406086 100644
--- a/chrome/renderer/resources/extensions/notifications_custom_bindings.js
+++ b/chrome/renderer/resources/extensions/notifications_custom_bindings.js
@@ -22,17 +22,20 @@ function replaceNotificationOptionURLs(notification_details, callback) {
   //  width: (optional) The maximum width of the image to be downloaded.
   //  height: (optional) The maximum height of the image to be downloaded.
   //  callback: A function to be called when the URL is complete. It
-  //    should accept an ImageData object and set the appropriate
-  //    field in the output of create.
-
-  // TODO(dewittj): Try to remove hard-coding of image sizes.
-  // |iconUrl| is required.
-  var url_specs = [{
-    path: notification_details.iconUrl,
-    width: 80,
-    height: 80,
-    callback: image_data_setter(notification_details, 'iconBitmap')
-  }];
+  //    should accept an ImageData object and set the appropriate
+  //    field in the output of create.
+
+  // TODO(dewittj): Try to remove hard-coding of image sizes.
+  // |iconUrl| might be optional for notification updates.
+  var url_specs = [];
+  if (notification_details.iconUrl) {
+    $Array.push(url_specs, {
+      path: notification_details.iconUrl,
+      width: 80,
+      height: 80,
+      callback: image_data_setter(notification_details, 'iconBitmap')
+    });
+  }
 
   // |imageUrl| is optional.
   if (notification_details.imageUrl) {
@@ -57,7 +60,12 @@ function replaceNotificationOptionURLs(notification_details, callback) {
           callback: image_data_setter(button_list[i], 'iconBitmap')
         });
       }
-    }
+    }
+  }
+
+  if (!url_specs.length) {
+    callback(true);
+    return;
   }
 
   var errors = 0;