cros: Add check for |should_send_rlz_ping| in RW_VPD

Reading from VPD is supported by StatisticsProvider so IMO we can reuse
the code. There will be a follow-up Chrome OS CL to deal with writing
to VPD specifically.

Bug: 820783
Change-Id: I57de7212ca3b5366731789f0836ab5c6fcca294f
Reviewed-on: https://chromium-review.googlesource.com/969942
Commit-Queue: Wenzhao (Colin) Zang <wzang@chromium.org>
Reviewed-by: Alexander Alekseev <alemate@chromium.org>
Reviewed-by: Roger Tawa <rogerta@chromium.org>
Cr-Commit-Position: refs/heads/master@{#545659}

diff --git a/rlz/DEPS b/rlz/DEPS
index aba5be2..9cab8e58 100644
--- a/rlz/DEPS
+++ b/rlz/DEPS

@@ -56,6 +56,7 @@
 
 include_rules = [
   "+build",
+  "+chromeos/system",
   "+net",  # This is only used when force_rlz_use_chrome_net=1 is passed to gyp.
   "+third_party/zlib",
 ]