Adding a test for measuring memory usage.

tools/perf/page_sets/top_25.json

 {
     "description": "Pages hand-picked for 2012 CrOS scrolling tuning efforts.",
     "archive_path": "../data/top_25.wpr",
     "credentials_path": "../data/credentials.json",
     "pages": [
         {
             "url": "https://www.google.com/#hl=en&q=barack+obama",
             "why": "top google property; a google tab is often open"
         },
         {
@@ skipping 43 matching lines @@
             "url": "http://en.blog.wordpress.com/2012/09/04/freshly-pressed-editors-picks-for-august-2012/",
             "why": "#18 (Alexa global), Picked an interesting post"
         },
         {
             "name": "Facebook",
             "url": "http://www.facebook.com/barackobama",
             "why": "top social,Public profile",
             "credentials": "facebook",
             "scroll_is_infinite": true,
             "stress_memory": {
-                "action": "compound",
+                "action": "compound_interaction",
                 "actions": [
                     {
-                        "action": "click_to_navigate",
+                        "action": "click_to_navigate_interaction",
                         "selector": "a[href=\"http://www.facebook.com/WomenforObama\"]"
                     },
                     {
-                        "action": "click_to_navigate",
+                        "action": "click_to_navigate_interaction",
                         "selector": "a[href=\"http://www.facebook.com/WomenforObama/info\"]"
                     },
                     {
-                        "action": "click_to_navigate",
+                        "action": "click_to_navigate_interaction",
                         "selector": "a[href=\"http://www.facebook.com/?ref=tn_tnmn\"]"
                     }
                 ]
             }
         },
         {
             "name": "LinkedIn",
             "url": "http://www.linkedin.com/in/linustorvalds",
             "why": "#12 (Alexa global),Public profile"
         },
@@ skipping 55 matching lines @@
         {
             "url": "http://sports.yahoo.com/",
             "why": "#1 Alexa sports"
         },
         {
             "url": "http://techcrunch.com",
             "why": "top tech blog"
         }
     ]
 }