Enable StorePendingItemInContext feature by default.

Also add StorePendingItemInContext flag to chrome://flags UI.

Bug: 899827
Change-Id: Id18fa102710de5273da0a53f0b78fe4f2c1c651e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1500594
Commit-Queue: Justin Cohen <justincohen@chromium.org>
Auto-Submit: Eugene But <eugenebut@chromium.org>
Reviewed-by: Justin Cohen <justincohen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#637683}
4 files changed