Set content-length header for httpResponses.

Set content-length header for httpResponses.

The client might wait forever if the server fails to close
the connection.

BUG=

Committed: https://crrev.com/9003aae151682bd9a416137c2a5bb2a8f1fc81e2
Cr-Commit-Position: refs/heads/master@{#291711}

[hush (inactive), 2014-08-22 22:58:08]

I see some android webview instrumentation tests flaky or just failing when I
run them locally, if the server does not set the response length. These tests
are the ones that open ssl connections, like AwSettingsTest#testAllowMixedMode

[hush (inactive), 2014-08-23 00:56:32]

PTAL

[Yaron, 2014-08-25 16:11:26]

lgtm

[hush (inactive), 2014-08-25 17:03:36]

The CQ bit was checked by hush@chromium.org

[commit-bot: I haz the power, 2014-08-25 17:04:31]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/hush@chromium.org/501603002/1

[commit-bot: I haz the power, 2014-08-25 17:58:13]

Committed patchset #1 (1) as b18b7691c865291a6333511c2df905a032d5402c

[commit-bot: I haz the power, 2014-09-10 02:35:35]

Patchset 1 (id:??) landed as
https://crrev.com/9003aae151682bd9a416137c2a5bb2a8f1fc81e2
Cr-Commit-Position: refs/heads/master@{#291711}