Add bisect-config-trying script and a few example configs.

tools/auto_bisect/configs/linux.perf_test.tab_switching.cfg

Index: tools/auto_bisect/configs/linux.perf_test.tab_switching.cfg
diff --git a/tools/auto_bisect/configs/linux.perf_test.tab_switching.cfg b/tools/auto_bisect/configs/linux.perf_test.tab_switching.cfg
new file mode 100644
index 0000000000000000000000000000000000000000..17c6c2c0129d1bfe2d1df768c50d0b807ee21dde
--- /dev/null
+++ b/tools/auto_bisect/configs/linux.perf_test.tab_switching.cfg
@@ -0,0 +1,11 @@
+# This config just runs the tab-switching command once.
+# http://build.chromium.org/p/tryserver.chromium.perf/builders/linux_perf_bisect/builds/689
+
+config = {
+  "command": "./tools/perf/run_benchmark -v tab_switching.typical_25 --browser=release",
+  "max_time_minutes": "30",
+  "repeat_count": "1",
+  "truncate_percent": "0"
+}
+
+# Workaround git try issue, see crbug.com/257689