Revert "remvoe duplicate impl for SkImageInfo flattening"

Reason: breaks chrome_mac_tests which still have non-imageinfo constructors

This reverts commit a06b8cf60b39bda93e9ef1a73579007b2b930d29.

BUG=

Review URL: https://codereview.chromium.org/103033005

git-svn-id: http://skia.googlecode.com/svn/trunk/include@12631 2bbb7eff-a529-9590-31e7-b0007b416f81
9 files changed