Support clipboardRead and clipboardWrite permission for hosted apps.

Support clipboardRead and clipboardWrite permission for hosted apps.

BUG=82024
TEST=none

Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=86244

[Erik does not do reviews, 2011-05-09 18:30:12]

Please file a bug for this issue with some more explanation of the purpose and
use case of the permission.

[dcheng, 2011-05-09 18:44:19]

I've create a bug with (hopefully) a good explanation of the use case.

[dcheng, 2011-05-16 22:01:57]

On 2011/05/09 18:44:19, dcheng wrote:
> I've create a bug with (hopefully) a good explanation of the use case.

So I've poked around a bit at this. The main issue is I'm not able to use the
usual chrome.test framework. I think with some modifications (though I'm not
entirely sure what yet), I'd be able to inject extension_apitest.js into the
hosted app pages as well. I'm not sure if this is desirable though.

I tried to take an alternative temporary approach to solve the problem, but it
turns out that apps can't use content scripts.

[dcheng, 2011-05-19 22:51:54]

Please take another look if you can. Thanks!

[Erik does not do reviews, 2011-05-20 21:49:01]

As discussed in IM, it seems like we should have tests for when one is enabled,
but not the other and when none are enabled.

http://codereview.chromium.org/6976002/diff/14001/chrome/browser/extensions/c...
File chrome/browser/extensions/clipboard_app_apitest.cc (right):

http://codereview.chromium.org/6976002/diff/14001/chrome/browser/extensions/c...
chrome/browser/extensions/clipboard_app_apitest.cc:29: L" 
document.body.addEventListener('copy', runTest2);"
This approach is a bit of a bummer since it depends on a timeout to function
properly.  Doesn't execCommand return false when it fails?

[dcheng, 2011-05-21 00:04:54]

I've updated the tests.

[Erik does not do reviews, 2011-05-22 17:38:51]

LGTM