GL_COVERAGE_BUFFER_BIT_NV  495 ppapi/lib/gl/include/GLES2/gl2ext.h #define GL_COVERAGE_BUFFER_BIT_NV                               0x8000
GL_COVERAGE_BUFFER_BIT_NV 1225 third_party/khronos/GLES2/gl2ext.h #define GL_COVERAGE_BUFFER_BIT_NV         0x00008000