Remove Settings::maxBeaconTransmission

The entry was introduced by [1] but it's used only by a test, so this
CL removes the entry and the test.

This is a preparation for introducing the quota management intrastructure
for keepalive requests.

1: https://src.chromium.org/viewvc/blink?view=rev&revision=173837

Bug: 695939
Change-Id: I3b252e07d179e75ef787e6251d0a34abb640ef8c
Reviewed-on: https://chromium-review.googlesource.com/828561
Reviewed-by: Kouhei Ueno <kouhei@chromium.org>
Reviewed-by: Takeshi Yoshino <tyoshino@chromium.org>
Commit-Queue: Yutaka Hirano <yhirano@chromium.org>
Cr-Commit-Position: refs/heads/master@{#525573}
4 files changed