Remove scanlineOrder switch statements that always do the same thing

I think these date back to GIF codec having a third value of this enum
that meant "interlaced" ?

Change-Id: Iaff11a55ad3cff44da2307149991a22447dfe746
Reviewed-on: https://skia-review.googlesource.com/119146
Reviewed-by: Leon Scroggins <scroggo@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
diff --git a/dm/DMSrcSink.cpp b/dm/DMSrcSink.cpp
index 6a14c63..4ddebb7 100644
--- a/dm/DMSrcSink.cpp
+++ b/dm/DMSrcSink.cpp
@@ -616,14 +616,9 @@
                     return "Could not start scanline decoder";
                 }
 
-                switch (codec->getScanlineOrder()) {
-                    case SkCodec::kTopDown_SkScanlineOrder:
-                    case SkCodec::kBottomUp_SkScanlineOrder:
-                        // We do not need to check the return value.  On an incomplete
-                        // image, memory will be filled with a default value.
-                        codec->getScanlines(dst, height, rowBytes);
-                        break;
-                }
+                // We do not need to check the return value.  On an incomplete
+                // image, memory will be filled with a default value.
+                codec->getScanlines(dst, height, rowBytes);
             }
 
             draw_to_canvas(canvas, bitmapInfo, dst, rowBytes, fDstColorType);