Adding page cycler benchmark on the key mobile sites archive.

tools/perf/benchmarks/page_cycler.py

Index: tools/perf/benchmarks/page_cycler.py
diff --git a/tools/perf/benchmarks/page_cycler.py b/tools/perf/benchmarks/page_cycler.py
index 7544f0e84c6362c10313d165f720d9cb4beeeea9..a649918aca3c1124edb02b1ea2b47bd21f3d1a22 100644
--- a/tools/perf/benchmarks/page_cycler.py
+++ b/tools/perf/benchmarks/page_cycler.py
@@ -96,6 +96,12 @@ class PageCyclerTop10Mobile(test.Test):
   options = {'pageset_repeat_iters': 10}
 
 
+class PageCyclerKeyMobileSites(test.Test):
+  test = page_cycler.PageCycler
+  page_set = 'page_sets/key_mobile_sites.json'
+  options = {'pageset_repeat_iters': 10}
+
+
 class PageCyclerToughLayoutCases(test.Test):
   test = page_cycler.PageCycler
   page_set = 'page_sets/tough_layout_cases.json'