Attempt to fix flake in FullTabDownloadTest.CF_DownloadFileFromPost.

Attempt to fix flake in FullTabDownloadTest.CF_DownloadFileFromPost.

Increase timeout for the file to appear from 2s to 3s, and take a
snapshot when it doesn't appear in time.

BUG=189099
TEST=chrome_frame_tests.exe

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=188401

[robertshield, 2013-03-14 21:06:55]

lgtm

[commit-bot: I haz the power, 2013-03-14 22:25:40]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/grt@chromium.org/12779010/2002

[commit-bot: I haz the power, 2013-03-15 00:08:17]

Sorry for I got bad news for ya.
Compile failed with a clobber build on win_rel.
http://build.chromium.org/p/tryserver.chromium/buildstatus?builder=win_rel&nu...
Your code is likely broken or HEAD is junk. Please ensure your
code is not broken then alert the build sheriffs.
Look at the try server FAQ for more details.

[commit-bot: I haz the power, 2013-03-15 01:19:13]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/grt@chromium.org/12779010/19001

[commit-bot: I haz the power, 2013-03-15 02:28:36]

Retried try job too often on win_rel for step(s) unit_tests
http://build.chromium.org/p/tryserver.chromium/buildstatus?builder=win_rel&nu...

[commit-bot: I haz the power, 2013-03-15 11:45:01]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/grt@chromium.org/12779010/19001

[commit-bot: I haz the power, 2013-03-15 15:57:55]

Change committed as 188401