Revert "Temporarily disable HWA decoding support."

This reverts commit e8ee3471a56a1c23e86687d9d90e59564c7ffb44.
Fixed the compile error

the ozone/media uses mesa header GL/gl.h. However, video.gypi didn't add it
in the include_dirs. So, that will result in 'fatal error: GL/gl.h: No such
file or directory'