[tools/perf] Add long running dual browser benchmark

Add a new benchmark for measuring memory during prolonged usage of
alternating browsers.

Benchmark is same as memory.dual_browser_test, but the test is run for
60 iterations and the browser is *not* restarted between page set
repeats.

BUG=623015
CQ_EXTRA_TRYBOTS=tryserver.chromium.perf:android_s5_perf_cq

Review-Url: https://codereview.chromium.org/2095923002
Cr-Commit-Position: refs/heads/master@{#402215}
1 file changed