Simple Cache: avoid extraneous stream 0 (http header) writes.

Simple Cache: avoid extraneous stream 0 (http header) writes.

These writes were not only wasteful, but they could cause corruption
if the existing EOF record didn't have a key SHA256; the new key
SHA256 would overwrite the existing one corrupting the entry.

BUG=615440
R=juliatuttle@chromium.org,rdsmith@chromium.org

Review-Url: https://codereview.chromium.org/2015263002
Cr-Commit-Position: refs/heads/master@{#396533}
(cherry picked from commit 6b66971b761a15a67982bef692619a96f306150d)

Committed: https://chromium.googlesource.com/chromium/src/+/53f45d9bb2f4c767fc1edbed08d31edecaeb4fff

[gavinp, 2016-05-31 14:49:43]

Description was changed from

==========
Simple Cache: avoid extraneous stream 0 (http header) writes.

These writes were not only wasteful, but they could cause corruption
if the existing EOF record didn't have a key SHA256; the new key
SHA256 would overwrite the existing one corrupting the entry.

BUG=615440
R=juliatuttle@chromium.org,rdsmith@chromium.org

Review-Url: https://codereview.chromium.org/2015263002
Cr-Commit-Position: refs/heads/master@{#396533}
(cherry picked from commit 6b66971b761a15a67982bef692619a96f306150d)
==========

to

==========
Simple Cache: avoid extraneous stream 0 (http header) writes.

These writes were not only wasteful, but they could cause corruption
if the existing EOF record didn't have a key SHA256; the new key
SHA256 would overwrite the existing one corrupting the entry.

BUG=615440
R=juliatuttle@chromium.org,rdsmith@chromium.org

Review-Url: https://codereview.chromium.org/2015263002
Cr-Commit-Position: refs/heads/master@{#396533}
(cherry picked from commit 6b66971b761a15a67982bef692619a96f306150d)

Committed:
https://chromium.googlesource.com/chromium/src/+/53f45d9bb2f4c767fc1edbed08d3...
==========

[gavinp, 2016-05-31 14:49:45]

Committed patchset #1 (id:1) manually as
53f45d9bb2f4c767fc1edbed08d31edecaeb4fff.