Fix GenerateDiff -- don't strip whitespace.
Fix GenerateDiff -- don't strip whitespace.

BUG=259434
R=iannucci

Review URL: https://chromiumcodereview.appspot.com/18408006

git-svn-id: bd64dd6fa6f3f0ed0c0666d1018379882b742947@211483 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

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