Cros system menu - Use WiFi strike-through image for "No networks" row
and tray icon.

This CL addresses the linked bug and rewrite NetworkIconSource to use
vector icon structs instead of ImageSkia for badges. This is
necessary because the badge needs to be painted to the same canvas
instead of overlaid on top so that we can use PATH_MODE_CLEAR.

Test with CL flag --shill-stub="wifi=none,eth=0". The item in the
system menu should have a strike through. The item in the tray should
as well.

Also test with other flags like --shill-stub="wifi=12,eth=0,vpn=1" to
verify other changes.

BUG=706453
TBR=stevenjb@chromium.org

Review-Url: https://codereview.chromium.org/2784133002
Cr-Commit-Position: refs/heads/master@{#461434}
7 files changed