Record the tab state during data use

DataUse.AppTabState UMA is recorded with the following dimensions.
  Upstream.AppBackground
  Upstream.AppForeground.TabBackground
  Upstream.AppForeground.TabForeground
  Downstream.AppBackground
  Downstream.AppForeground.TabBackground
  Downstream.AppForeground.TabForeground

BUG=673820

Review-Url: https://codereview.chromium.org/2583703002
Cr-Commit-Position: refs/heads/master@{#439742}
11 files changed