Fixed an uninitialized variable in the AnalysisCanvas.

Fixed an uninitialized variable in the AnalysisCanvas.  This can
only occur when we haven't drawn anything and as a result the
color_ member needs to be initialized to transparent.

BUG=412377
Committed: https://crrev.com/4b2c60f37cedebd465c7ba897384b208a0a27c08
Cr-Commit-Position: refs/heads/master@{#294217}

[hendrikw, 2014-09-10 00:18:05]

hendrikw@chromium.org changed reviewers:
+ junov@chromium.org, vmpstr@chromium.org

[hendrikw, 2014-09-10 00:18:51]

Please review this, thanks!

[vmpstr, 2014-09-10 00:20:58]

lgtm, please format the description to be 72 col

[Justin Novosad, 2014-09-10 18:00:18]

On 2014/09/10 00:20:58, vmpstr wrote:
> lgtm, please format the description to be 72 col

lgtm

[hendrikw, 2014-09-10 18:25:24]

The CQ bit was checked by hendrikw@chromium.org

[commit-bot: I haz the power, 2014-09-10 18:26:14]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/hendrikw@chromium.org/552633004/1

[commit-bot: I haz the power, 2014-09-10 20:35:47]

Committed patchset #1 (id:1) as 48a523bd18168c2766eb888956dd9c777f5f9780

[commit-bot: I haz the power, 2014-09-10 20:40:26]

Patchset 1 (id:??) landed as
https://crrev.com/4b2c60f37cedebd465c7ba897384b208a0a27c08
Cr-Commit-Position: refs/heads/master@{#294217}