Clean up code in keyboard_overlay.js

There is no case of remaining id in new-shortcuts dictionary.
Because all of them are deleted by above code.

Change-Id: I0e9c971e58d811617fee957bf9864ce091ebab5b
Reviewed-on: https://chromium-review.googlesource.com/1186921
Commit-Queue: Jinho Bang <jinho.bang@samsung.com>
Reviewed-by: Steven Bennetts <stevenjb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#589760}

chrome/browser/resources/chromeos/keyboard_overlay.js

@@ -975,12 +975,8 @@ function initKeyboardLayout2() {
     'switch window<>SEARCH': 'keyboardOverlayF4',
   };
   var shortcutDataCache = keyboardOverlayData['shortcut'];
-  for (var shortcutId in newShortcuts) {
+  for (var shortcutId in newShortcuts)
     shortcutDataCache[shortcutId] = newShortcuts[shortcutId];
-    delete newShortcuts[shortcutId];
-  }
-  for (var remainingId in newShortcuts)
-    shortcutDataCache[remainingId] = newShortcuts[remainingId];
 }
 
 /**