system_api: Remove kResolveNetworkProxy constant.

This is no longer used.

BUG=chromium:703217
TEST=none

Change-Id: I97f03a875fb2da39636c1b815cb7fe88bfec6ae1
Reviewed-on: https://chromium-review.googlesource.com/535915
Commit-Ready: Dan Erat <derat@chromium.org>
Tested-by: Dan Erat <derat@chromium.org>
Reviewed-by: Justin TerAvest <teravest@chromium.org>
1 file changed