Pin keyboard use enter to submit when focus is not on a button.

chrome/browser/resources/chromeos/quick_unlock/pin_keyboard.js

Index: chrome/browser/resources/chromeos/quick_unlock/pin_keyboard.js
diff --git a/chrome/browser/resources/chromeos/quick_unlock/pin_keyboard.js b/chrome/browser/resources/chromeos/quick_unlock/pin_keyboard.js
index dfc111d4c5fcd7c32df8aa1e7a95762d0894bfbb..a4204294e8d91c277bd003b3d7195f2304d7ecd6 100644
--- a/chrome/browser/resources/chromeos/quick_unlock/pin_keyboard.js
+++ b/chrome/browser/resources/chromeos/quick_unlock/pin_keyboard.js
@@ -35,15 +35,42 @@ Polymer({
     }
   },
 
+  // Flag to check focus on next focus.
+  checkFocus_: false,
+  // The current focused element.
+  focusedElement_: undefined,
+
   /** Transfers focus to the input element. */
   focus: function() {
     this.$$('#pin-input').focus();
+    this.focusedElement_ = document.activeElement;
+  },
+
+  /** Called when a pin keyboard button has focus. */
+  onButtonFocus_: function(event, detail) {
+    // If the button has been tabbed here it is the current element with focus.
+    if (this.checkFocus_) {
+      this.focusedElement_ = document.activeElement;
+      this.checkFocus_ = false;
+    }
+  },
+
+  /** Called when a pin keyboard has a key pressed. */
+  onButtonKeyDown_: function(event, detail) {
+    // Only if tab has been pressed do we want change the focus.
+    if (event.keyCode == 9)
+      this.checkFocus_ = true;
   },
 
   /** Called when a keypad number has been tapped. */
   onNumberTap_: function(event, detail) {
     var numberValue = event.target.getAttribute('value');
     this.value += numberValue;
+
+    // If the tabbed element is clicked we want to keep the focus, otherwise
+    // transfer focus to the input.
+    if (this.focusedElement_ != event.target)
+      this.focus();
   },
 
   /** Fires a submit event with the current PIN value. */