vpython: Specify dependency on pywin32

TBR: phoglund@webrtc.org
No-Try: True
Bug: chromium:749668
Change-Id: Ifb3398d67b57caf0bb34e01b8de06c26a08a4aee
Reviewed-on: https://webrtc-review.googlesource.com/53140
Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org>
Reviewed-by: Oleh Prypin <oprypin@webrtc.org>
Commit-Queue: Oleh Prypin <oprypin@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#22019}
diff --git a/.vpython b/.vpython
index cf74427..ea4c93e 100644
--- a/.vpython
+++ b/.vpython
@@ -30,3 +30,16 @@
   name: "infra/python/wheels/psutil/${platform}_${py_python}_${py_abi}"
   version: "version:5.2.2"
 >
+
+# Used by:
+#   build/toolchain/win
+wheel: <
+  name: "infra/python/wheels/pypiwin32/${vpython_platform}"
+  version: "version:219"
+  match_tag: <
+    platform: "win32"
+  >
+  match_tag: <
+    platform: "win_amd64"
+  >
+>