Fix Unpremul Index8 tests

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 264 matching lines @@
         case kIndex_8_SkColorType: {
             SkColorTable* colorTable = bitmap.getColorTable();
             SkPMColor* colorPtr = const_cast<SkPMColor*>(colorTable->readColors());
             SkOpts::RGBA_to_rgbA(colorPtr, colorPtr, colorTable->count());
             break;
         }
         default:
             // No need to premultiply kGray or k565 outputs.
             break;
     }
+
+    // In the kIndex_8 case, the canvas won't even try to draw unless we mark the
+    // bitmap as kPremul.
+    bitmap.setAlphaType(kPremul_SkAlphaType);
 }
 
 bool get_decode_info(SkImageInfo* decodeInfo, SkColorType canvasColorType,
                      CodecSrc::DstColorType dstColorType) {
     switch (dstColorType) {
         case CodecSrc::kIndex8_Always_DstColorType:
             if (kRGB_565_SkColorType == canvasColorType) {
                 return false;
             }
             *decodeInfo = decodeInfo->makeColorType(kIndex_8_SkColorType);
@@ skipping 1083 matching lines @@
             skr.visit<void>(i, drawsAsSingletonPictures);
         }
         SkAutoTUnref<SkPicture> macroPic(macroRec.endRecordingAsPicture());
 
         canvas->drawPicture(macroPic);
         return check_against_reference(bitmap, src, fSink);
     });
 }
 
 }  // namespace DM