[Merge-58] Preserve use stats of existing Wallet cards when syncing.

[Merge-58] Preserve use stats of existing Wallet cards when syncing.

Load the use stats from disk when saving Wallet Cards.

Add specific logic to overwrite a Wallet card use data in case the
metadata gets delayed. The previous logic was keep most recent which
resulted in making old card seem like they were just used.

BUG=700486
Review-Url: https://codereview.chromium.org/2741233002
Cr-Commit-Position: refs/heads/master@{#456395}
(cherry picked from commit 109e10b0a48a1f09d242562611c2556b12a29da6)

Review-Url: https://codereview.chromium.org/2759183003 .
Cr-Commit-Position: refs/branch-heads/3029@{#308}
Cr-Branched-From: 939b32ee5ba05c396eef3fd992822fcca9a2e262-refs/heads/master@{#454471}
Committed: https://chromium.googlesource.com/chromium/src/+/c558a4c40f4b3dd67cc6f50a879bc1f6e16fbe18

[sebsg, 2017-03-20 19:27:17]

Description was changed from

==========
[Merge-58] Preserve use stats of existing Wallet cards when syncing.

Load the use stats from disk when saving Wallet Cards.

Add specific logic to overwrite a Wallet card use data in case the
metadata gets delayed. The previous logic was keep most recent which
resulted in making old card seem like they were just used.

BUG=700486

Review-Url: https://codereview.chromium.org/2741233002
Cr-Commit-Position: refs/heads/master@{#456395}
(cherry picked from commit 109e10b0a48a1f09d242562611c2556b12a29da6)
==========

to

==========
[Merge-58] Preserve use stats of existing Wallet cards when syncing.

Load the use stats from disk when saving Wallet Cards.

Add specific logic to overwrite a Wallet card use data in case the
metadata gets delayed. The previous logic was keep most recent which
resulted in making old card seem like they were just used.

BUG=700486

Review-Url: https://codereview.chromium.org/2741233002
Cr-Commit-Position: refs/heads/master@{#456395}
(cherry picked from commit 109e10b0a48a1f09d242562611c2556b12a29da6)

Review-Url: https://codereview.chromium.org/2759183003 .
Cr-Commit-Position: refs/branch-heads/3029@{#308}
Cr-Branched-From:
939b32ee5ba05c396eef3fd992822fcca9a2e262-refs/heads/master@{#454471}
Committed:
https://chromium.googlesource.com/chromium/src/+/c558a4c40f4b3dd67cc6f50a879b...
==========

[sebsg, 2017-03-20 19:27:20]

Committed patchset #1 (id:1) manually as
c558a4c40f4b3dd67cc6f50a879bc1f6e16fbe18.