Only run kStripe_Mode on JPEGs

dm/DMSrcSink.cpp

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "DMSrcSink.h"
 #include "SkAndroidCodec.h"
 #include "SkCodec.h"
@@ skipping 466 matching lines @@
 
             // Decode odd stripes
             if (SkCodec::kSuccess != codec->startScanlineDecode(decodeInfo, NULL, colorPtr,
                                                                 colorCountPtr)) {
                 return "Could not start scanline decoder";
             }
 
             // This mode was designed to test the new skip scanlines API in libjpeg-turbo.
             // Jpegs have kTopDown_SkScanlineOrder, and at this time, it is not interesting
             // to run this test for image types that do not have this scanline ordering.
-            if (SkCodec::kTopDown_SkScanlineOrder != codec->getScanlineOrder()) {
-                return Error::Nonfatal("kStripe test is only interesting for kTopDown codecs.");
-            }
+            // We only run this on Jpeg, which is always kTopDown.
+            SkASSERT(SkCodec::kTopDown_SkScanlineOrder == codec->getScanlineOrder());
 
             for (int i = 0; i < numStripes; i += 2) {
                 // Skip a stripe
                 const int linesToSkip = SkTMin(stripeHeight, height - i * stripeHeight);
                 codec->skipScanlines(linesToSkip);
 
                 // Read a stripe
                 const int startY = (i + 1) * stripeHeight;
                 const int linesToRead = SkTMin(stripeHeight, height - startY);
                 if (linesToRead > 0) {
@@ skipping 1063 matching lines @@
             skr.visit(i, drawsAsSingletonPictures);
         }
         sk_sp<SkPicture> macroPic(macroRec.finishRecordingAsPicture());
 
         canvas->drawPicture(macroPic);
         return check_against_reference(bitmap, src, fSink);
     });
 }
 
 }  // namespace DM