Improve CounterTrack perf test
Merge pull request #676 from petrcermak/counter_track_perf_test

Improve CounterTrack perf test
Add low/high details visualisation modes for counter tracks
Merge pull request #678 from petrcermak/counter_track_design_switch

Add low/high details visualisation modes for counter tracks
support content_shell

chromium content_shell for linux uses different version string.
this string is fixed and it's not updated automatically.
('content_shell_version': '19.77.34.5') in content_shell.gypi
if the browser is content_shell, the version will have '77.34.5' delimiter.
so we can support content_shell to use tracing by checking the delimiter.

BUG=674
Merge pull request #680 from fnwinter/support_content_shell

support content_shell
Add generate_trace_viewer script that produces an importable trace_viewer to bin/trace_viwer.html