Revert of [android] Stop using isolate.py for data dependency management.

build/secondary/tools/swarming_client/BUILD.gn

Index: build/secondary/tools/swarming_client/BUILD.gn
diff --git a/build/secondary/tools/swarming_client/BUILD.gn b/build/secondary/tools/swarming_client/BUILD.gn
new file mode 100644
index 0000000000000000000000000000000000000000..f4860523c7c31d9379aa6c9e44ec73d0b2c99c1c
--- /dev/null
+++ b/build/secondary/tools/swarming_client/BUILD.gn
@@ -0,0 +1,14 @@
+# Copyright 2016 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.
+
+group("isolate_py") {
+  _py_files =
+      read_file("//build/secondary/tools/swarming_client/isolate.pydeps",
+                "list lines")
+
+  # Filter out comments.
+  set_sources_assignment_filter([ "#*" ])
+  sources = _py_files
+  data = sources
+}