Rename all isolate_dependency_* to files.

chrome/angle_unittests.isolate

 # Copyright 2013 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.
 {
   'includes': [
     '../base/base.isolate',
   ],
   'conditions': [
     ['OS=="android" or OS=="linux" or OS=="mac" or OS=="win"', {
       'variables': {
         'command': [
           '<(PRODUCT_DIR)/angle_unittests<(EXECUTABLE_SUFFIX)',
         ],
-        'isolate_dependency_tracked': [
+        'files': [
           '<(PRODUCT_DIR)/angle_unittests<(EXECUTABLE_SUFFIX)',
         ],
       },
     }],
   ],
 }