ntp4: record app launch source

chrome/browser/resources/ntp4/most_visited_page.js

Index: chrome/browser/resources/ntp4/most_visited_page.js
diff --git a/chrome/browser/resources/ntp4/most_visited_page.js b/chrome/browser/resources/ntp4/most_visited_page.js
index a6631c8f75bd0fd4874d463dfa1e4d9596b7e9c1..ebcd2a40ffebcbc4f516ec6ba11be415568d7e62 100644
--- a/chrome/browser/resources/ntp4/most_visited_page.js
+++ b/chrome/browser/resources/ntp4/most_visited_page.js
@@ -118,6 +118,12 @@ cr.define('ntp4', function() {
         this.blacklist_();
         e.preventDefault();
       } else {
+        // Records an app launch from the most visited page (Chrome will decide
+        // whether the url is an app).
+        // TODO(estade): don't convert to string.
+        chrome.send('recordAppLaunchByURL',

[Rick Byers, 2011/08/03 14:41:11]

Is replacing the ping with a click handler really equivalent?  I thought ping
was designed to handle a broader set of situations - eg. right click and "open
in new tab".  Too bad there's no "on anchor activate" DOM event - that's really
what you want I think.  I suppose we have to decide whether we'd rather use
pings, switch the anchors to plain divs, or miss out on some launches.

[Evan Stade, 2011/08/03 22:11:22]

I would have thought you were right, but ping doesn't seem to work that way
(open in new tab/window from the context menu doesn't send a ping).

Also, right click + open URL in new tab kind of sucks for recently closed,
because it doesn't restore session state (e.g. back/forward history).

[Rick Byers, 2011/08/04 00:32:21]

That sucks - seems like a bug according to the spec:
http://www.whatwg.org/specs/web-apps/current-work/multipage/links.html#hyperl....
 Anyway, it's your call, but I'd prefer if you at least left a comment pointing
out that the app launches are only recorded for regular clicks.  It might be
worth getting Arv's input on this when he's back.

+                    [this.href, String(ntp4.APP_LAUNCH.NTP_MOST_VISITED)]);
+        // Records the index of this tile.
         chrome.send('recordInHistogram', ['NTP_MostVisited', this.index, 8]);
       }
     },