Rename isolate_dependency_tracked to files.

icu.isolate

 # 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.
 {
   'conditions': [
     # iOS always has the icu data in the bundle and we don't have to
     # specify the dependency for iOS here.
     ['icu_use_data_file_flag==1 and (OS=="linux" or OS=="win" or OS=="mac" or OS=="android")', {
       'variables': {
-        'isolate_dependency_tracked': [
+        'files': [
           '<(PRODUCT_DIR)/icudtl.dat',
         ],
       },
     }],
     # When icu data is not used, other platforms link it statically.
     ['icu_use_data_file_flag==0 and OS=="win"', {
       'variables': {
-          'isolate_dependency_tracked': [
+          'files': [
             '<(PRODUCT_DIR)/icudt.dll',
         ],
       },
     }],
   ],
 }