Rename isolate_dependency_tracked to files.

That's the new name, and the next swarming_client roll will refuse the old name.

R=jshin@chromium.org
BUG=

Review URL: https://codereview.chromium.org/607413006

git-svn-id: http://src.chromium.org/svn/trunk/deps/third_party/icu52@292317 4ff67af0-8c30-449e-8e8b-ad334ec8d88c
diff --git a/icu.isolate b/icu.isolate
index b106ccc..3c27e24 100644
--- a/icu.isolate
+++ b/icu.isolate
@@ -7,7 +7,7 @@
     # 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',
         ],
       },
@@ -15,7 +15,7 @@
     # 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',
         ],
       },