How to enable verbose logging

At times, it is handy to have extra logging for input event dispatch, so that we can see what (and how) components are handling event dispatch. We can enable verbose logging for a particular component by adding the --verbose flag to its invocation.

For example, Root Presenter and Scenic components can issue verbose logging.

If a test has a CMX file that starts a Scenic component in its injected-services clause, that looks like the following:

{
    "facets": {
        "fuchsia.test": {
            "injected-services": {
                "fuchsia.ui.scenic.Scenic": "fuchsia-pkg://fuchsia.com/scenic#meta/scenic.cmx",

To add extra logging for input event dispatch, modify the line that contains "fuchsia.ui.scenic.Scenic", in the following way:

                  "fuchsia.ui.scenic.Scenic": [ "fuchsia-pkg://fuchsia.com/scenic#meta/scenic.cmx", "--verbose=2" ],

Note that each service instance of Scenic (or Root Presenter) must be modified, unless you know which service is invoked first.

This is identical to modifying a sysmgr services configuration file.