Enable both static and dynamically linked libpng

gyp/common_variables.gypi

 # Copyright 2012 The Android Open Source Project
 #
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 {
   # Get ready for the ugly...
   #
   # - We have to nest our variables dictionaries multiple levels deep, so that
   #   this and other gyp files can rely on previously-set variable values in
@@ skipping 153 matching lines @@
 
       # This variable allows the user to customize the optimization level used
       # by the compiler.  The user should be aware that this has different
       # meanings for different compilers and should exercise caution when
       # overriding it.
       [ 'skia_os == "win"', {
         'skia_release_optimization_level%': '<(skia_default_vs_optimization_level)',
       }, {
         'skia_release_optimization_level%': '<(skia_default_gcc_optimization_level)',
       }],
-      [ 'skia_os == "android"', {
-          # skia_libpng_static - instead of linking libpng with '-lpng' and
-          #     including the headers from '/usr/include/png.h', compile and
-          #     statically link the version of libpng in
-          #     third_party/externals/libpng.
-          'skia_libpng_static%': '0',
-      }, {
-          'skia_libpng_static%': '1',
-      }],
       [ 'skia_sanitizer', {
         'skia_clang_build': 1,
         'skia_keep_frame_pointer': 1,
       }, {
         'skia_clang_build%': 0,
         'skia_keep_frame_pointer%': 0,
       }],
       [ 'skia_shared_lib or skia_sanitizer or skia_os == "android"', {
           'skia_pic%' : 1,
         }, {
@@ skipping 46 matching lines @@
     'skia_moz2d%': 0,
     'skia_is_bot%': '<!(python -c "import os; print os.environ.get(\'CHROME_HEADLESS\', 0)")',
     'skia_egl%': '<(skia_egl)',
 
     # These are referenced by our .gypi files that list files (e.g. core.gypi)
     #
     'skia_src_path%': '../src',
     'skia_include_path%': '../include',
   },
 }