SkThreadPool: tweak two little things that have been annoying me

SkThreadPool: tweak two little things that have been annoying me
 1) it's pretty annoying that SkThreadPool doesn't include SkRunnable for us;
 2) add wait() so we don't have to keep using SkAutoTDelete/free() to wait for completion.

BUG=

Committed: http://code.google.com/p/skia/source/detail?r=11711

[scroggo, 2013-10-10 15:51:44]

On 2013/10/10 15:42:31, mtklein wrote:

lgtm

[commit-bot: I haz the power, 2013-10-10 16:01:18]

CQ is trying da patch. Follow status at
https://skia-tree-status.appspot.com/cq/mtklein@google.com/26470005/4001

[commit-bot: I haz the power, 2013-10-10 16:01:23]

Presubmit check for 26470005-4001 failed and returned exit status 1.

Running presubmit commit checks ...

** Presubmit ERRORS **
Since the CL is editing public API, you must have an LGTM from one of:
('reed@chromium.org', 'reed@google.com', 'bsalomon@chromium.org',
'bsalomon@google.com')

[scroggo, 2013-10-10 16:10:58]

Adding reed@ to approve the public API

[reed1, 2013-10-10 17:12:15]

lgtm

[commit-bot: I haz the power, 2013-10-10 17:31:31]

CQ is trying da patch. Follow status at
https://skia-tree-status.appspot.com/cq/mtklein@google.com/26470005/4001

[commit-bot: I haz the power, 2013-10-10 18:49:10]

Change committed as 11711