Add CodecZeroInit test to DMSrcSink

This should not cause any diffs on Gold.

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1577853004

Review URL: https://codereview.chromium.org/1577853004

3 files changed, 19 insertions, 4 deletions

diff --git a/dm/DM.cpp b/dm/DM.cpp
index 0e36c07367..7302ebc270 100644
--- a/dm/DM.cpp
+++ b/dm/DM.cpp
@@ -232,6 +232,9 @@ static void push_codec_src(Path path, CodecSrc::Mode mode, CodecSrc::DstColorTyp
         case CodecSrc::kCodec_Mode:
             folder.append("codec");
             break;
+        case CodecSrc::kCodecZeroInit_Mode:
+            folder.append("codec_zero_init");
+            break;
         case CodecSrc::kScanline_Mode:
             folder.append("scanline");
             break;
@@ -311,8 +314,8 @@ static void push_codec_srcs(Path path) {
     // SkJpegCodec natively supports scaling to: 0.125, 0.25, 0.375, 0.5, 0.625, 0.75, 0.875
     const float nativeScales[] = { 0.125f, 0.25f, 0.375f, 0.5f, 0.625f, 0.750f, 0.875f, 1.0f };
 
-    const CodecSrc::Mode nativeModes[] = { CodecSrc::kCodec_Mode, CodecSrc::kScanline_Mode,
-            CodecSrc::kStripe_Mode, CodecSrc::kSubset_Mode };
+    const CodecSrc::Mode nativeModes[] = { CodecSrc::kCodec_Mode, CodecSrc::kCodecZeroInit_Mode,
+            CodecSrc::kScanline_Mode, CodecSrc::kStripe_Mode, CodecSrc::kSubset_Mode };
 
     CodecSrc::DstColorType colorTypes[3];
     uint32_t numColorTypes;
diff --git a/dm/DMSrcSink.cpp b/dm/DMSrcSink.cpp
index c9bdcf6706..bbfa5199e6 100644
--- a/dm/DMSrcSink.cpp
+++ b/dm/DMSrcSink.cpp
@@ -316,14 +316,22 @@ Error CodecSrc::draw(SkCanvas* canvas) const {
     }
 
     SkBitmap bitmap;
-    if (!bitmap.tryAllocPixels(decodeInfo, nullptr, colorTable.get())) {
+    SkPixelRefFactory* factory = nullptr;
+    SkMallocPixelRef::ZeroedPRFactory zeroFactory;
+    SkCodec::Options options;
+    if (kCodecZeroInit_Mode == fMode) {
+        factory = &zeroFactory;
+        options.fZeroInitialized = SkCodec::kYes_ZeroInitialized;
+    }
+    if (!bitmap.tryAllocPixels(decodeInfo, factory, colorTable.get())) {
         return SkStringPrintf("Image(%s) is too large (%d x %d)", fPath.c_str(),
                               decodeInfo.width(), decodeInfo.height());
     }
 
     switch (fMode) {
+        case kCodecZeroInit_Mode:
         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
diff --git a/dm/DMSrcSink.h b/dm/DMSrcSink.h
index 6645807286..def7cc9f5c 100644
--- a/dm/DMSrcSink.h
+++ b/dm/DMSrcSink.h
@@ -104,6 +104,10 @@ class CodecSrc : public Src {
 public:
     enum Mode {
         kCodec_Mode,
+        // We choose to test only one mode with zero initialized memory.
+        // This will exercise all of the interesting cases in SkSwizzler
+        // without doubling the size of our test suite.
+        kCodecZeroInit_Mode,
         kScanline_Mode,
         kStripe_Mode, // Tests the skipping of scanlines
         kSubset_Mode, // For codecs that support subsets directly.