Convert .ninja_log files to chrome's about:tracing format.
Idea from Nick Carter, initial implementation from Richard Smith.
$ ./ninjatracing Converts one (or several) .ninja_log files into chrome's about:tracing format Usage: ninja -C $BUILDDIR ninjatracing $BUILDDIR/.ninja_log > trace.json By default this will show build timing results for the most recent (possibly incremental) build. To show build timing results for every target, whether built in the last build or previously, use --showall. Note that this will overlap multiple builds and will thus exaggerate build parallelism. (When using --showall, ideally rm $BUILDDIR/.ninja_log and do a clean build. If you don't have time for a clean build, at least run `ninja -C $BUILDDIR -t recompact` first to remove no-longer-built targets.) The results can be converted from .json format to .html format, for easier loading into about:tracing, using trace2html from: https://github.com/catapult-project/catapult/blob/master/tracing/bin/trace2html