
In chrome extension, contentWindow is undefined for security reason.
The function goog.dom.getFrameContentDocument is modified to support
chrome extension.

R=chrishenry,pupius,arv
DELTA=6  (0 added, 5 deleted, 1 changed)


Revision created by MOE tool push_codebase.
MOE_MIGRATION=3573


git-svn-id: 35241bd708fe29f1f6c7a4322d322e99ff93b95e@1363 0b95b8e8-c90f-11de-9d4f-f947ee5921c8

homer6/google-closure-library,thinkfuse/google-closure,knutwalker/google-closure-library,thinkfuse/google-closure,homer6/google-closure-library,thinkfuse/google-closure,KgDesignes/closure-library,knutwalker/google-closure-library,KgDesignes/closure-library,KgDesignes/closure-library,homer6/google-closure-library