Adds a function to read the current trace system property value, and
sets the trace tags to it, do be used as a sysprop change callback.
Change-Id: Ia6336652173aa5b07188898736c2c795a69fe79a
Basic tracing functionality to cutils, which can be turned on at start,
or dynamically controlled by the frameworks. The goal is for hardware
modules to add tracing that will be controlled by their respective
services.
Change-Id: I84eeb7d6be0038f734e719074fa4a2fae4ffe9c0