Add CodecZeroInit test to DMSrcSink

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 303 matching lines @@
         colorPtr = const_cast<SkPMColor*>(colorTable->readColors());
         colorCountPtr = &maxColors;
     }
 
     SkBitmap bitmap;
     if (!bitmap.tryAllocPixels(decodeInfo, nullptr, colorTable.get())) {
         return SkStringPrintf("Image(%s) is too large (%d x %d)", fPath.c_str(),
                               decodeInfo.width(), decodeInfo.height());
     }
 
+    SkCodec::Options options;
     switch (fMode) {
+        case kCodecZeroInit_Mode:
+            options.fZeroInitialized = SkCodec::kYes_ZeroInitialized;
+            bitmap.eraseColor(0);

[scroggo, 2016/01/12 22:27:46]

This won't work for index8 bitmaps. Instead, we can use an allocator which calls
calloc.

[mtklein, 2016/01/12 22:51:22]

e.g. SkMallocPixelRef::NewZeroed() / SkMallocPixelRef::ZeroedPRFactory.

[msarett, 2016/01/13 14:58:16]

Done.

+            // Intentional fall through.
         case kCodec_Mode: {
-            switch (codec->getPixels(decodeInfo, bitmap.getPixels(), bitmap.rowBytes(), nullptr,
+            switch (codec->getPixels(decodeInfo, bitmap.getPixels(), bitmap.rowBytes(), &options,
                     colorPtr, colorCountPtr)) {
                 case SkCodec::kSuccess:
                     // We consider incomplete to be valid, since we should still decode what is
                     // available.
                 case SkCodec::kIncompleteInput:
                     break;
                 case SkCodec::kInvalidConversion:
                     return Error::Nonfatal("Incompatible colortype conversion");
                 default:
                     // Everything else is considered a failure.
@@ skipping 964 matching lines @@
             skr.visit<void>(i, drawsAsSingletonPictures);
         }
         SkAutoTUnref<SkPicture> macroPic(macroRec.endRecordingAsPicture());
 
         canvas->drawPicture(macroPic);
         return check_against_reference(bitmap, src, fSink);
     });
 }
 
 }  // namespace DM