dm changes

src/codec/SkCodec_libpng.cpp

Index: src/codec/SkCodec_libpng.cpp
diff --git a/src/codec/SkCodec_libpng.cpp b/src/codec/SkCodec_libpng.cpp
index 9cd382092e25da6ff77cd902ab1ae85c32a8ba31..0134c1b83cd887dd5910957137bac8b7353894fe 100644
--- a/src/codec/SkCodec_libpng.cpp
+++ b/src/codec/SkCodec_libpng.cpp
@@ -624,8 +624,9 @@ public:
             SkCodecPrintf("setjmp long jump!\n");
             return SkImageGenerator::kInvalidInput;
         }
-
-        png_read_rows(fCodec->fPng_ptr, png_bytepp_NULL, png_bytepp_NULL, count);
+        for (int i = 0; i < count; i++) {

[scroggo, 2015/05/21 19:32:36]

This should perhaps be a separate CL, since it fixes a bug.

+            png_read_rows(fCodec->fPng_ptr, &fSrcRow, png_bytepp_NULL, 1);

[scroggo, 2015/05/21 19:32:36]

Maybe add a comment here that explains the potential tradeoff we've made by
putting this in a loop.

It's possible that it would be faster to pass count to png_read_rows, but it
would mean allocating more memory. (On the other hand, maybe there isn't much of
a tradeoff. I saw you were looking at the code in png_read_rows - is it more
efficient to do multiple rows at once? Or do they just have their own loop?)

+        }
         return SkImageGenerator::kSuccess;
     }