app_shell: Add version number in user agent

app_shell: Add version number in user agent

Some sites sniff the Chrome version number, so app_shell needs to
provide one.

BUG=407236
TEST=app_shell_unittests ShellContentClientTest.UserAgentFormat

Committed: https://crrev.com/bf89045bff6e60d18bd91ae29c8e675db1d9ab6a
Cr-Commit-Position: refs/heads/master@{#292063}

[James Cook, 2014-08-26 22:32:10]

jamescook@chromium.org changed reviewers:
+ derat@chromium.org

[James Cook, 2014-08-26 22:32:10]

derat, PTAL

[Daniel Erat, 2014-08-26 22:36:03]

lgtm

[James Cook, 2014-08-26 23:00:12]

The CQ bit was checked by jamescook@chromium.org

[commit-bot: I haz the power, 2014-08-26 23:02:16]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/jamescook@chromium.org/505403003/1

[commit-bot: I haz the power, 2014-08-27 00:15:31]

FYI, CQ is re-trying this CL (attempt #1).
The failing builders are:
  win_chromium_x64_rel_swarming on tryserver.chromium.win
(http://build.chromium.org/p/tryserver.chromium.win/builders/win_chromium_x64_...)

[commit-bot: I haz the power, 2014-08-27 01:17:10]

Committed patchset #1 (1) as 40a0ec9559ed0993b0edbfe8cbcff15f1a40d082

[commit-bot: I haz the power, 2014-09-10 02:48:33]

Patchset 1 (id:??) landed as
https://crrev.com/bf89045bff6e60d18bd91ae29c8e675db1d9ab6a
Cr-Commit-Position: refs/heads/master@{#292063}