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/samplecode/SamplePicture.cpp b/samplecode/SamplePicture.cpp
index 2f7d691..66289af 100644
--- a/samplecode/SamplePicture.cpp
+++ b/samplecode/SamplePicture.cpp
@@ -40,9 +40,7 @@
 
         if (SkImageDecoder::DecodeStream(stream, &bm, SkBitmap::kNo_Config,
                                          SkImageDecoder::kDecodeBounds_Mode)) {
-            SkImageInfo info;
-            bm.asImageInfo(&info);
-            SkPixelRef* pr = new SkImageRef_GlobalPool(info, stream, 1);
+            SkPixelRef* pr = new SkImageRef_GlobalPool(stream, bm.config(), 1);
             bm.setPixelRef(pr)->unref();
         }
     }