Chrome remote control multipage tests: Add interactions.

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 41 matching lines @@
         {
             "name": "Wordpress",
             "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
+            "scroll_is_infinite": true,
+            "interaction_sequence": [

[nduca, 2012/11/07 18:55:57]

so this part doesn't make sense without a bit more code. Can you make the
compound interaction as we discussed before?

I'd like this file to say this:
"interactions": ["scroll", "compound"]
"compound_interaction": [
  {"interaction": "click_to_navigate",
   "selector": ...},
]

[marja, 2012/11/08 10:24:00]

Ok, for this I needed to add compound interactions (compound interaction is also
a PageInteraction, and the json description of it must obey the same format...)
and the compound interaction runner.

So, I added this:
"tests": {
    "stress_memory": {
        "action": "compound",
        "actions": [
        {
            "action": "click_to_navigate",
            "selector": ...
         }, ...

So, every test is one interaction (which can be a compound interaction), and in
the next CL, I can describe the scroll interaction in the same format. Ok?

And now the memory test runner is very simple:
interaction_data = page.tests['stress_memory']
i =
page_interaction.FindClassWithName(interaction_data['action'])(interaction_data)
i.PerformInteraction(page, tab)
# get the mem histograms

+                {
+                    "action": "click_to_navigate",
+                    "selector": "a[href=\"http://www.facebook.com/WomenforObama\"]"
+                },
+                {
+                    "action": "click_to_navigate",
+                    "selector": "a[href=\"http://www.facebook.com/WomenforObama/info\"]"
+                },
+                {
+                    "action": "click_to_navigate",
+                    "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"
         },
         {
             "name": "Wikipedia (1 tab)",
             "url": "http://en.wikipedia.org/wiki/Wikipedia",
             "why": "#6 (Alexa) most visited worldwide,Picked an interesting page"
@@ skipping 51 matching lines @@
         {
             "url": "http://sports.yahoo.com/",
             "why": "#1 Alexa sports"
         },
         {
             "url": "http://techcrunch.com",
             "why": "top tech blog"
         }
     ]
 }