Add "prodchannel" attribute in component updater update requests.

Add "prodchannel" attribute in component updater update requests.

In order to be compatible with the version 2 of the update protocol and
existing config files, we need to serialize "prodchannel" as part of the
<request> element; "updaterchannel" is not enough (though it is also required
for logging via the version 3 protocol).

BUG=332551
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=244364

[waffles, 2014-01-10 19:10:28]

Hi Sorin, please take a look at this short CL to add prodchannel.

I also beefed up the test a bit; previously I think our test for "arch=" would
have given a false positive because of "nacl-arch=".

[Sorin Jianu, 2014-01-10 20:47:09]

lgtm

Thank you!

[commit-bot: I haz the power, 2014-01-10 20:55:14]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/waffles@chromium.org/134583002/1

[commit-bot: I haz the power, 2014-01-10 23:53:02]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/waffles@chromium.org/134583002/1

[commit-bot: I haz the power, 2014-01-11 22:25:53]

Change committed as 244364