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This moves initialization of parameters to SetSubclassProperties.
The next step is to clean up initialization to use a common program
descriptor. In that patch, I'll change these functions to
CheckSubclassProperties, so that I can DCHECK that I didn't change
anything.

BUG=667966
CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_trusty_blink_rel

Review-Url: https://codereview.chromium.org/2626823002
Cr-Commit-Position: refs/heads/master@{#442761}