Revert of Enable both static and dynamically linked libpng

gyp/common_variables.gypi

Index: gyp/common_variables.gypi
diff --git a/gyp/common_variables.gypi b/gyp/common_variables.gypi
index 8fb4620b826663a6a1cc1ddc1267ed344894a262..80ab7c91ed7c996761a5e61d43f179c7eb73cceb 100644
--- a/gyp/common_variables.gypi
+++ b/gyp/common_variables.gypi
@@ -164,6 +164,15 @@
         '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,