GL_COVERAGE_BUFFERS_NV  490 ppapi/lib/gl/include/GLES2/gl2ext.h #define GL_COVERAGE_BUFFERS_NV                                  0x8ED3
GL_COVERAGE_BUFFERS_NV 1220 third_party/khronos/GLES2/gl2ext.h #define GL_COVERAGE_BUFFERS_NV            0x8ED3