Add a release procedure to SkMallocPixelRef; remove SkDataPixelRef

gyp/core.gypi

 # Include this gypi to include all 'core' files
 # The parent gyp/gypi file must define
 #       'skia_src_path'     e.g. skia/trunk/src
 #       'skia_include_path' e.g. skia/trunk/include
 #
 # The skia build defines these in common_variables.gypi
 #
 {
     'sources': [
         '<(skia_src_path)/core/ARGB32_Clamp_Bilinear_BitmapShader.h',
@@ skipping 181 matching lines @@
         '<(skia_src_path)/core/SkTypefaceCache.cpp',
         '<(skia_src_path)/core/SkTypefaceCache.h',
         '<(skia_src_path)/core/SkUnPreMultiply.cpp',
         '<(skia_src_path)/core/SkUtils.cpp',
         '<(skia_src_path)/core/SkValidatingReadBuffer.cpp',
         '<(skia_src_path)/core/SkWriter32.cpp',
         '<(skia_src_path)/core/SkXfermode.cpp',
 
         '<(skia_src_path)/doc/SkDocument.cpp',
 
-        '<(skia_src_path)/image/SkDataPixelRef.cpp',
         '<(skia_src_path)/image/SkImage.cpp',
         '<(skia_src_path)/image/SkImagePriv.cpp',
         '<(skia_src_path)/image/SkImage_Codec.cpp',
 #        '<(skia_src_path)/image/SkImage_Gpu.cpp',
         '<(skia_src_path)/image/SkImage_Picture.cpp',
         '<(skia_src_path)/image/SkImage_Raster.cpp',
         '<(skia_src_path)/image/SkSurface.cpp',
 #        '<(skia_src_path)/image/SkSurface_Gpu.cpp',
         '<(skia_src_path)/image/SkSurface_Picture.cpp',
         '<(skia_src_path)/image/SkSurface_Raster.cpp',
@@ skipping 144 matching lines @@
         '<(skia_src_path)/pathops/SkPathOpsPoint.h',
         '<(skia_src_path)/pathops/SkPathOpsQuad.h',
         '<(skia_src_path)/pathops/SkPathOpsRect.h',
         '<(skia_src_path)/pathops/SkPathOpsTriangle.h',
         '<(skia_src_path)/pathops/SkPathOpsTypes.h',
         '<(skia_src_path)/pathops/SkPathWriter.h',
         '<(skia_src_path)/pathops/SkQuarticRoot.h',
         '<(skia_src_path)/pathops/SkReduceOrder.h',
     ],
 }