Implements peer connection stats measurements in WebRTC call test.

tools/perf/page_sets/webrtc_cases.py

Index: tools/perf/page_sets/webrtc_cases.py
diff --git a/tools/perf/page_sets/webrtc_cases.py b/tools/perf/page_sets/webrtc_cases.py
index cc61f7a2d2cccfa8d88d56eb94aea0ca9e37cb34..f39bf06958a4e3eaa2b2617be9bc4fa8f6073ac5 100644
--- a/tools/perf/page_sets/webrtc_cases.py
+++ b/tools/perf/page_sets/webrtc_cases.py
@@ -5,12 +5,55 @@ from telemetry.page import page as page_module
 from telemetry.page import page_set as page_set_module
 
 
+TRACK_CREATED_PEER_CONNECTIONS = '''

[tonyg, 2014/09/29 16:45:22]

This looks significant enough to warrant pulling out to a .js file which we read
in. For example, see tools/perf/metrics/media.js

[phoglund_chromium, 2014/09/30 13:37:48]

Done.

+  function getReportsAsDicts(getStatsResult) {
+    var result = [];
+    getStatsResult.forEach(function(report) {
+      var values = {};
+      report.names().forEach(function(name) {
+        values[name] = report.stat(name);
+      });
+      result.push(values);
+    });
+    return result;
+  }
+
+  window.peerConnectionReports = [];

[tonyg, 2014/09/29 16:45:22]

Looks like everything besides this should go into the functional closure to
avoid polluting window.

[phoglund_chromium, 2014/09/30 13:37:48]

Done.

+  function gatherStatsFromOneConnection(peerConnection) {
+    var connectionId = window.peerConnectionReports.length;
+    window.peerConnectionReports.push([]);
+    var pollIntervalMs = 1000;
+
+    setInterval(function() {
+      peerConnection.getStats(function(response) {
+        var reports = getReportsAsDicts(response.result());
+        window.peerConnectionReports[connectionId].push(reports);
+      });
+    }, pollIntervalMs);
+  }
+
+  webkitRTCPeerConnection = (function() {
+    var originalConstructor = webkitRTCPeerConnection;
+    return function() {
+      // Bind the incoming arguments to the original constructor.
+      var args = [null].concat(Array.prototype.slice.call(arguments));
+      var factoryFunction = originalConstructor.bind.apply(
+          originalConstructor, args);
+
+      // Create the object and track it.
+      var peerConnection = new factoryFunction();
+      gatherStatsFromOneConnection(peerConnection);
+      return peerConnection;
+    }
+  })();
+'''
+
+
 class WebrtcCasesPage(page_module.Page):
 
   def __init__(self, url, page_set):
     super(WebrtcCasesPage, self).__init__(url=url, page_set=page_set)
 
-
 class Page1(WebrtcCasesPage):
 
   """ Why: Simple test page only showing a local video stream """
@@ -34,6 +77,7 @@ class Page2(WebrtcCasesPage):
     super(Page2, self).__init__(
       url='file://third_party/webrtc/samples/js/demos/html/pc1.html',
       page_set=page_set)
+    self.script_to_evaluate_on_commit = TRACK_CREATED_PEER_CONNECTIONS

[tonyg, 2014/09/29 16:45:22]

Why is this on page2 but not page1? If that's a mistake, I recommend moving this
injection into the Measurement because any page set with the webrtc measurement
requires it. If that's not a mistake, then this is the correct place, but I'd
like to understand why.

[phoglund_chromium, 2014/09/30 13:37:48]

The first test page only does a getUserMedia and puts the media stream into a
local video tag, whereas page 2 (and 3, which I'll just now rebase in), sets up
peer connections as well.

So for page 1, the measurement will not measure anything.

 
   def RunEndure(self, action_runner):

[tonyg, 2014/09/29 16:45:22]

Unrelated: Endure is gone. I think this can be removed now.

[phoglund_chromium, 2014/09/30 13:37:48]

Done.

     action_runner.ClickElement('button[id="btn1"]')