Add SkCodec, including PNG implementation.

dm/DMSrcSink.cpp

 #include "DMSrcSink.h"
 #include "SamplePipeControllers.h"
 #include "SkCommonFlags.h"
+#include "SkCodec.h"
 #include "SkDocument.h"
 #include "SkMultiPictureDraw.h"
 #include "SkNullCanvas.h"
 #include "SkOSFile.h"
 #include "SkPictureRecorder.h"
 #include "SkRandom.h"
 #include "SkSVGCanvas.h"
 #include "SkStream.h"
 #include "SkXMLWriter.h"
 
+DEFINE_bool(codec, false, "Use SkCodec instead of SkImageDecoder");
+
 namespace DM {
 
 GMSrc::GMSrc(skiagm::GMRegistry::Factory factory) : fFactory(factory) {}
 
 Error GMSrc::draw(SkCanvas* canvas) const {
     SkAutoTDelete<skiagm::GM> gm(fFactory(NULL));
     canvas->concat(gm->getInitialTransform());
     gm->draw(canvas);
     return "";
 }
@@ skipping 14 matching lines @@
 
 Error ImageSrc::draw(SkCanvas* canvas) const {
     SkAutoTUnref<SkData> encoded(SkData::NewFromFileName(fPath.c_str()));
     if (!encoded) {
         return SkStringPrintf("Couldn't read %s.", fPath.c_str());
     }
     const SkColorType dstColorType = canvas->imageInfo().colorType();
     if (fDivisor == 0) {
         // Decode the full image.
         SkBitmap bitmap;
-        if (!SkImageDecoder::DecodeMemory(encoded->data(), encoded->size(), &bitmap,
-                                          dstColorType, SkImageDecoder::kDecodePixels_Mode)) {
-            return SkStringPrintf("Couldn't decode %s.", fPath.c_str());
+        if (FLAGS_codec) {
+            SkAutoTDelete<SkCodec> codec(SkCodec::NewFromData(encoded));
+            if (!codec) {
+                return SkStringPrintf("Couldn't decode %s.", fPath.c_str());
+            }
+            SkImageInfo info;
+            if (!codec->getInfo(&info)) {
+                return SkStringPrintf("Couldn't getInfo %s.", fPath.c_str());
+            }
+            info = info.makeColorType(dstColorType);
+            if (info.alphaType() == kUnpremul_SkAlphaType) {
+                // FIXME: Currently we cannot draw unpremultiplied sources.
+                info = info.makeAlphaType(kPremul_SkAlphaType);
+            }
+            bitmap.allocPixels(info);
+            SkAutoLockPixels alp(bitmap);

[djsollen, 2015/02/25 16:02:19]

aren't the pixels locked during allocPixels if you use the default (heap)
allocator?  Also what about calling tryAllocPixels and throw an error in case
the image was so large we couldn't hold it?  I think it is better to not crash
in that event and let the other tests continue to run.  

[scroggo, 2015/02/25 18:00:54]

Yes. In fact I initially left this line out, if you look at my earlier
patchsets. That said, the fact that they are locked appears to be an
implementation detail. The fact that they are locked is not guaranteed by the
comments.
Done.

+            const SkImageGenerator::Result result = codec->getPixels(info, bitmap.getPixels(),
+                                                                     bitmap.rowBytes());
+            if (result != SkImageGenerator::kSuccess) {
+                return SkStringPrintf("Couldn't getPixels %s.", fPath.c_str());
+            }
+        } else {

[djsollen, 2015/02/25 16:02:19]

else if

[scroggo, 2015/02/25 18:00:54]

In this case, I actually like the current code better, since it more clearly (at
least to me) delineates between FLAGS_codec and !FLAGS_codec.

+            if (!SkImageDecoder::DecodeMemory(encoded->data(), encoded->size(), &bitmap,
+                                              dstColorType, SkImageDecoder::kDecodePixels_Mode)) {
+                return SkStringPrintf("Couldn't decode %s.", fPath.c_str());
+            }
         }
         encoded.reset((SkData*)NULL);  // Might as well drop this when we're done with it.
         canvas->drawBitmap(bitmap, 0,0);
         return "";
     }
     // Decode subsets.  This is a little involved.
     SkAutoTDelete<SkMemoryStream> stream(new SkMemoryStream(encoded));
     SkAutoTDelete<SkImageDecoder> decoder(SkImageDecoder::Factory(stream.get()));
     if (!decoder) {
         return SkStringPrintf("Can't find a good decoder for %s.", fPath.c_str());
@@ skipping 396 matching lines @@
             surfaces.unrefAll();
             return "";
         }
         SkISize size() const SK_OVERRIDE { return fSize; }
         Name name() const SK_OVERRIDE { sk_throw(); return ""; }  // No one should be calling this.
     } proxy(fW, fH, pic, src.size());
     return fSink->draw(proxy, bitmap, stream, log);
 }
 
 }  // namespace DM