Add SkCodec, including PNG implementation.

gyp/libpng.gyp

 # Copyright 2014 Google Inc.
 #
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 {
   'variables': {
     'skia_warnings_as_errors': 0,
   },
   'targets': [
@@ skipping 14 matching lines @@
             ],
             'direct_dependent_settings': {
               'include_dirs': [
                 '../third_party/externals/libpng',
               ],
             },
             'cflags': [
               '-w',
               '-fvisibility=hidden',
             ],
+            'conditions': [
+              ['not arm_neon', {
+                'defines': [
+                    # FIXME: Why is this needed? Without it, pngpriv.h sets it
+                    # to 2 if __ARM_NEON is defined, but shouldn't __ARM_NEON
+                    # not be defined since arm_neon is 0?
+                    'PNG_ARM_NEON_OPT=0',

[scroggo, 2015/02/26 20:34:21]

Does someone who knows NEON better than I do (I think we have a few on this CL)
have an idea why this is needed?

I'm trying to build for iOS using the following GYP_DEFINES:
"skia_os='ios' skia_arch_type='arm' armv7=1 arm_neon=0"

(This appears to be how we build iOS on the trybot I tried; part of that is
redundant, but oh well.)

It looks like __ARM_NEON is incorrectly defined, but I haven't figured out how.

+                ],
+              }],
+            ],
+            'actions': [
+              {
+                'action_name': 'generate_pngconf',
+                'variables' : {
+                  'prebuilt': '../third_party/externals/libpng/scripts/pnglibconf.h.prebuilt',
+                  'generated': '../third_party/externals/libpng/pnglibconf.h',
+                },
+                'inputs': [
+                  '<(prebuilt)',
+                ],
+                'outputs': [
+                  '<(generated)',
+                ],
+                'action': ['python', 'copy_file.py', '<(prebuilt)', '<(generated)'],
+              },
+            ],
             'sources': [
               '../third_party/externals/libpng/png.c',
               '../third_party/externals/libpng/pngerror.c',
-              '../third_party/externals/libpng/pnggccrd.c',
               '../third_party/externals/libpng/pngget.c',
               '../third_party/externals/libpng/pngmem.c',
               '../third_party/externals/libpng/pngpread.c',
               '../third_party/externals/libpng/pngread.c',
               '../third_party/externals/libpng/pngrio.c',
               '../third_party/externals/libpng/pngrtran.c',
               '../third_party/externals/libpng/pngrutil.c',
               '../third_party/externals/libpng/pngset.c',
               '../third_party/externals/libpng/pngtrans.c',
-              '../third_party/externals/libpng/pngvcrd.c',
               '../third_party/externals/libpng/pngwio.c',
               '../third_party/externals/libpng/pngwrite.c',
               '../third_party/externals/libpng/pngwtran.c',
               '../third_party/externals/libpng/pngwutil.c',
             ],
           }, {  # not skia_libpng_static
             'type': 'none',
             'conditions': [
               [ 'skia_os == "android"',
                 {
@@ skipping 20 matching lines @@
                   },
                 }
               ]
             ]
           }
         ]
       ],
     },
   ]
 }