Displays each benchmark/skp with a graph showing a series of frame times.
Use the space bar to skip to the next benchmark.
Adds an option to hit ESC to quit VisualBench. Useful in fullscreen mode.
Review URL: https://codereview.chromium.org/1336043003
The newly created VisualLightweightBenchModule is just the old VisualBench.cpp, but gutted to only include timing code.
Future CLs will harden this abstraction, but for this CL the module owns a backpointer to VisualBench.cpp for a couple of calls.
BUG=skia:
Review URL: https://codereview.chromium.org/1304083007
