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@12631 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/include/core/SkPicture.h b/include/core/SkPicture.h
index cd6b3bc..bce343e 100644
--- a/include/core/SkPicture.h
+++ b/include/core/SkPicture.h
@@ -220,11 +220,10 @@
     // V14: Add flags word to PathRef serialization
     // V15: Remove A1 bitmpa config (and renumber remaining configs)
     // V16: Move SkPath's isOval flag to SkPathRef
-    // V17: Changes to PixelRef to store SkImageInfo
 #ifndef DELETE_THIS_CODE_WHEN_SKPS_ARE_REBUILT_AT_V16_AND_ALL_OTHER_INSTANCES_TOO
     static const uint32_t PRIOR_PICTURE_VERSION = 15;  // TODO: remove when .skps regenerated
 #endif
-    static const uint32_t PICTURE_VERSION = 17;
+    static const uint32_t PICTURE_VERSION = 16;
 
     // fPlayback, fRecord, fWidth & fHeight are protected to allow derived classes to
     // install their own SkPicturePlayback-derived players,SkPictureRecord-derived