Force save changes when Enter is pressed for the controls with buffered updates.

chrome/browser/resources/print_preview/settings/copies_settings.js

Index: chrome/browser/resources/print_preview/settings/copies_settings.js
diff --git a/chrome/browser/resources/print_preview/settings/copies_settings.js b/chrome/browser/resources/print_preview/settings/copies_settings.js
index 189ada79c46ae29f58e0a0a15351458d3f1c6ccc..0c6e783c880a78c317b094cea6bc92fbaab8e59d 100644
--- a/chrome/browser/resources/print_preview/settings/copies_settings.js
+++ b/chrome/browser/resources/print_preview/settings/copies_settings.js
@@ -75,6 +75,10 @@ cr.define('print_preview', function() {
       fadeOutOption(this.getElement(), true);
       this.tracker.add(
           this.getChildElement('input.copies'),
+          'keydown',
+          this.onTextfieldKeyDown_.bind(this));
+      this.tracker.add(
+          this.getChildElement('input.copies'),
           'input',
           this.onTextfieldInput_.bind(this));
       this.tracker.add(
@@ -168,6 +172,7 @@ cr.define('print_preview', function() {
      * @private
      */
     onTextfieldTimeout_: function() {
+      this.textfieldTimeout_ = null;
       var copiesVal = this.getChildElement('input.copies').value;
       if (copiesVal != '') {
         this.copiesTicketItem_.updateValue(copiesVal);
@@ -175,6 +180,20 @@ cr.define('print_preview', function() {
     },
 
     /**
+     * Called when a key is pressed on the custom input.
+     * @param {Event} event Contains the key that was pressed.
+     * @private
+     */
+    onTextfieldKeyDown_: function(event) {
+      if (event.keyCode == 13 /*enter*/) {
+        if (this.textfieldTimeout_) {
+          clearTimeout(this.textfieldTimeout_);
+        }
+        this.onTextfieldTimeout_();
+      }
+    },
+
+    /**
      * Called when a input event occurs on the textfield. Starts an input
      * timeout.
      * @private