Add --comm filter to report_sample.py
This is modelled off the --comm flag in pprof_proto_generator.py.
It's also similar to `perf script --comms`. Perhaps I should add an alias
I had to also move the filename from being a positional argument to
a -i/--record_file argument, because otherwise if I ran
$ report_sample.py --comm DefaultPool1 my_perf.data
Then my_perf.data was interpreted as an additional comm argument.
The -i brings this tool into line with the other tools too.
No docs needed to be updated -- they all use the implicit perf.data default.
Also add a few tests.
This is particularly useful for filtering to the UI thread for
visualising in Flamescope.
BUG=200118152
Change-Id: Idd6dc5a85fa60156bab30aca672c3cd69c402119
Test: Ran test/test.py -p TestReportSample.\*
8 files changed
