Files app: Move common/js/externs.js to externs/*.

ui/file_manager/file_manager/common/js/lru_cache_unittest.js

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 function testLRUCache() {
   var cache = new LRUCache(3);
 
   // Querying by non-existent key will get null.
   assertEquals(null, cache.get('a'));
 
@@ skipping 98 matching lines @@
   assertEquals(8, cache.size());
 
   // Adding an item whose size is bigger than the max size will be ignored.
   cache.put('f', 'FFF', 11);
   assertEquals(null, cache.get('f'));
   assertEquals('AAA', cache.get('a'));
   assertEquals('DDD', cache.get('d'));
   assertEquals(8, cache.size());
 }
 
+/** @constructor */
 function RandomNumberGenerator(seed) {
   this.x = seed;
 }
 
 RandomNumberGenerator.prototype.random = function() {
   this.x = (32453 * this.x + 254119) % (1 << 24);
   return this.x >> 4;
 };
 
 function generateRandom3letters(generator) {
@@ skipping 40 matching lines @@
   cache.put('b', 'valueB');
   cache.put('c', 'valueC');
   assertEquals('valueA', cache.peek('a'));
   assertEquals('valueB', cache.peek('b'));
   assertEquals('valueC', cache.peek('c'));
   cache.setMaxSize(1);
   assertEquals(null, cache.peek('a'));
   assertEquals(null, cache.peek('b'));
   assertEquals('valueC', cache.peek('c'));
 }