Revert "SkBitmap now really stores SkImageInfo -- config is just a ruse"

BUG=skia:

Review URL: https://codereview.chromium.org/147733004

git-svn-id: http://skia.googlecode.com/svn/trunk@13395 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/tests/ImageDecodingTest.cpp b/tests/ImageDecodingTest.cpp
index 2e0225a..81f9006 100644
--- a/tests/ImageDecodingTest.cpp
+++ b/tests/ImageDecodingTest.cpp
@@ -333,7 +333,10 @@
     SkASSERT(stream != NULL);
     SkASSERT(stream->rewind());
     SkASSERT(stream->unique());
-    SkColorType colorType = bitmap->colorType();
+    SkColorType colorType;
+    if (!SkBitmapConfigToColorType(bitmap->config(), &colorType)) {
+        return NULL;
+    }
     SkDecodingImageGenerator::Options opts(sampleSize, ditherImage, colorType);
     SkAutoTDelete<SkImageGenerator> gen(
         SkDecodingImageGenerator::Create(stream, opts));