Enable proguard for ChromeShell

Enable proguard for ChromeShell

Currently we don't have any real uses of proguard in non-internal code. This
makes it really easy to break the proguard rules.

This enables proguard for ChromeShell with a fairly conservative configuration
(for example, everything in org.chromium.** is kept).

Committed: https://crrev.com/0be554b77381ec6703d673fb7f688dac97736f07
Cr-Commit-Position: refs/heads/master@{#327547}

[cjhopman, 2015-04-27 18:46:26]

cjhopman@chromium.org changed reviewers:
+ nyquist@chromium.org

[cjhopman, 2015-04-27 18:46:26]

nyquist: *

[nyquist, 2015-04-27 23:15:38]

lgtm. including everything in org.chromium.** simplified things quite a bit.

[cjhopman, 2015-04-29 18:21:21]

The CQ bit was checked by cjhopman@chromium.org

[commit-bot: I haz the power, 2015-04-29 18:21:38]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1107653003/1

[cjhopman, 2015-04-29 18:22:06]

The CQ bit was unchecked by cjhopman@chromium.org

[cjhopman, 2015-04-29 18:22:17]

The CQ bit was checked by cjhopman@chromium.org

[commit-bot: I haz the power, 2015-04-29 18:22:44]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1107653003/1

[commit-bot: I haz the power, 2015-04-29 19:31:19]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-04-29 19:33:10]

Patchset 1 (id:??) landed as
https://crrev.com/0be554b77381ec6703d673fb7f688dac97736f07
Cr-Commit-Position: refs/heads/master@{#327547}