blink: Allow image decodes to work without a Platform

blink: Allow image decodes to work without a Platform

I'm using blinks image decoding in a small application to test skia's
gpu rasterization via our command buffer.  Unfortunately, blink requires
a Platform to be created for the sole purpose of exposing maxDecodedBytes.

There are other locations in blink where we check the existence of
the Platform, I'm doing the same here.

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=196545

[hendrikw, 2015-06-04 23:17:37]

hendrikw@chromium.org changed reviewers:
+ kbr@chromium.org

[hendrikw, 2015-06-04 23:17:48]

PTAL, thanks!

[Ken Russell (switch to Gerrit), 2015-06-04 23:22:14]

lgtm

[hendrikw, 2015-06-04 23:34:43]

The CQ bit was checked by hendrikw@chromium.org

[commit-bot: I haz the power, 2015-06-04 23:34:59]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1161203004/1

[commit-bot: I haz the power, 2015-06-05 02:03:08]

Committed patchset #1 (id:1) as
https://src.chromium.org/viewvc/blink?view=rev&revision=196545