Rename all isolate_dependency_* to files.

base/base_unittests.isolate

Index: base/base_unittests.isolate
diff --git a/base/base_unittests.isolate b/base/base_unittests.isolate
index a7a0723790718be93706a6ce9f1fedba94afe898..c5c192c00eafde4bb7d07476c00d4a47f67c5a8f 100644
--- a/base/base_unittests.isolate
+++ b/base/base_unittests.isolate
@@ -5,7 +5,7 @@
   'conditions': [
     ['OS=="android" or OS=="linux" or OS=="mac" or OS=="win"', {
       'variables': {
-        'isolate_dependency_untracked': [
+        'files': [
           'test/data/',
         ],
       },
@@ -19,21 +19,21 @@
           '--brave-new-test-launcher',
           '--test-launcher-bot-mode',
         ],
-        'isolate_dependency_tracked': [
+        'files': [
           '../testing/xvfb.py',
         ],
       },
     }],
     ['OS=="linux" and use_ozone==0', {
       'variables': {
-        'isolate_dependency_tracked': [
+        'files': [
           '<(PRODUCT_DIR)/xdisplaycheck<(EXECUTABLE_SUFFIX)',
         ],
       },
     }],
     ['OS=="linux" or OS=="mac" or OS=="win"', {
       'variables': {
-        'isolate_dependency_tracked': [
+        'files': [
           '../testing/test_env.py',
           '<(PRODUCT_DIR)/base_unittests<(EXECUTABLE_SUFFIX)',
         ],
@@ -52,7 +52,7 @@
     }],
     ['OS=="win" and (fastbuild==0 or fastbuild==1)', {
       'variables': {
-        'isolate_dependency_untracked': [
+        'files': [
           '<(PRODUCT_DIR)/base_unittests.exe.pdb',
         ],
       },