Don't attempt to inline aliases of external names during collapse properties as all the sets can not be accounted for.
Fixes issue 931
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Created by MOE: http://code.google.com/p/moe-java
MOE_MIGRATED_REVID=43187988
Add unprefixed page visibility api externs from
http://www.w3.org/TR/page-visibility/
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Created by MOE: http://code.google.com/p/moe-java
MOE_MIGRATED_REVID=43195381