Adding page cycler benchmark on the key mobile sites archive.

tools/perf/test-info.json

 {
   "_description":"This file contains info about our performance test suites, used by the perf dashboard (http://chromeperf.appspot.com).",
   "blink_perf":{
     "description":"Runs all enabled benchmarks in third_party/WebKit/PerformanceTests/",
     "code":[
       "chrome/src/tools/perf/measurements/blink_perf.py",
       "third_party/WebKit/PerformanceTests/"
     ]
   },
   "browsermark": {
@@ skipping 147 matching lines @@
   },
   "page_cycler.pica":{
     "description":"Loading benchmark for the Polymer toolkit's [Pica](http://www.polymer-project.org/polymer-all/projects/pica/index.html) demo app"
   },
   "page_cycler.netsim.top_10":{
     "description":"Page loading benchmark for a set of 10 top pages recorded in June, 2013.  Pages are loaded under the simplisticly simulated bandwidth and RTT constraints of a cable modem (5Mbit/s down, 1Mbit/s up, 28ms RTT). Contention is realistically simulated, but slow start is not. DNS lookups are 'free'."
   },
   "page_cycler.top_10_mobile":{
     "description":"Page load time benchmark for the top 10 mobile web pages. Runs against pages recorded in November, 2013."
   },
+  "page_cycler.key_mobile_sites":{
+    "description":"Page load time benchmark for key mobile sites."
+  },
   "page_cycler.tough_layout_cases":{
     "description":"Page loading benchmark for the slowest layouts observed in the Alexa top 1 million sites in July 2013."
   },
   "page_cycler.typical_25":{
     "description":"Page load time benchmark for a 25 typical web pages. Designed to represent typical, not highly optimized or highly popular web sites. Runs against pages recorded in April, 2013."
   },
   "robohornet_pro":{
     "description":"Milliseconds to complete the [RoboHornetPro demo by Microsoft](http://ie.microsoft.com/testdrive/performance/robohornetpro/)"
   },
   "peacekeeper":{
@@ skipping 37 matching lines @@
     "description":"Measures warm startup time with a dirty profile.",
     "comment":"The same as startup.warm.blank_page, except for the user profile that's used. Set up in tools/build/scripts/master/factory/chromium_factory.py."
   },
   "sunspider":{
     "description":"Performance on the [SunSpider JavaScript benchmark](http://www.webkit.org/perf/sunspider/sunspider.html)"
   },
   "tab_switching.top_10":{
     "description":"This test records the MPArch.RWH_TabSwitchPaintDuration histogram, which is a measure of the time between when a tab was requested to be shown, and when first paint occurred. The script opens 10 pages in different tabs, waits for them to load, and then switches to each tab and records the metric. The pages were chosen from Alexa top ranking sites."
   }
 }