Update refernces to Blink's Platform API (chrome)

Update refernces to Blink's Platform API (chrome)

These headers have moved from Source/Platform/chromium/public to
public/platform. This CL updates chrome's references to the old location to
point to the new location. After this CL lands, I'll remove the forwarding
headers that are letting these references still work.

TBR=jamesr@chromium.org
BUG=239545
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=203133

[commit-bot: I haz the power, 2013-05-30 04:40:57]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/abarth@chromium.org/16109004/1

[jamesr, 2013-05-30 04:42:23]

I have OWNERS authority on zero of these files - you should probably tbr darin. 
Patch seems fine.

[abarth-chromium, 2013-05-30 04:45:27]

+darin

ok.  I can't edit the description because it will mess up the commit-queue.

[darin (slow to review), 2013-05-30 04:48:43]

Awesome, LGTM

[commit-bot: I haz the power, 2013-05-30 05:33:13]

Retried try job too often on linux_aura for step(s) browser_tests
http://build.chromium.org/p/tryserver.chromium/buildstatus?builder=linux_aura...

[commit-bot: I haz the power, 2013-05-30 05:43:57]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/abarth@chromium.org/16109004/21001

[commit-bot: I haz the power, 2013-05-30 12:40:15]

Change committed as 203133