Clean up pak loading.

Clean up pak loading.

- kEmptyPakContents was malformed; fix it
- chrome.pak was deleted half a year ago for iOS Chrome; don't try to load it

BUG=410411
TEST=no visible change

Committed: https://crrev.com/b34c55a6d60b5941fa54e2b214533cf8e5377675
Cr-Commit-Position: refs/heads/master@{#297210}

[Avi (use Gerrit), 2014-09-29 17:35:23]

avi@chromium.org changed reviewers:
+ tony@chromium.org

[Avi (use Gerrit), 2014-09-29 17:35:24]

I'm having trouble with the build machinery in
https://codereview.chromium.org/537063002/ so I'm landing pieces separately.
This is identical to what you OKed in that patch.

[tony, 2014-09-29 17:47:22]

LGTM

[Avi (use Gerrit), 2014-09-29 17:50:58]

The CQ bit was checked by avi@chromium.org

[commit-bot: I haz the power, 2014-09-29 17:51:56]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/611103002/1

[commit-bot: I haz the power, 2014-09-29 18:20:01]

Committed patchset #1 (id:1) as a6214ad10ff4a2119ba7ca5ddd4896995f67b3b5

[commit-bot: I haz the power, 2014-09-29 18:21:08]

Patchset 1 (id:??) landed as
https://crrev.com/b34c55a6d60b5941fa54e2b214533cf8e5377675
Cr-Commit-Position: refs/heads/master@{#297210}