Fix directory traversal in extension_resources.cc. Adds test case, which is complicated by several…

Fix directory traversal in extension_resources.cc.  Adds test case, which is complicated by several other pre-existing checks.
BUG=161836
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=169949

[Tom Sepez, 2012-11-26 20:44:09]

Adding suggested owner @kalman, please review.

[not at google - send to devlin, 2012-11-26 20:49:33]

lgtm

[commit-bot: I haz the power, 2012-11-27 21:19:46]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/tsepez@chromium.org/11308204/1

[commit-bot: I haz the power, 2012-11-27 21:56:28]

Sorry for I got bad news for ya.
Compile failed with a clobber build on win.
http://build.chromium.org/p/tryserver.chromium/buildstatus?builder=win&number...
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, 2012-11-27 22:51:11]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/tsepez@chromium.org/11308204/1

[commit-bot: I haz the power, 2012-11-28 15:04:36]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/tsepez@chromium.org/11308204/1

[commit-bot: I haz the power, 2012-11-28 15:27:23]

Change committed as 169949