void webkit_memory_pressure_settings_set_kill_threshold ( WebKitMemoryPressureSettings* settings, gdouble value )
value as the fraction of the defined memory limit where the process will be killed.
The threshold must be a value bigger or equal to 0. A value of 0 means that the process
is never killed. If the threshold is not 0, then it must be bigger than the strict threshold
settings. The threshold can also have values bigger than 1. The default value is 0.