Preparation CL for WebRTC performance test using promise-based getStats

chrome/test/data/webrtc/peerconnection_getstats.js

Index: chrome/test/data/webrtc/peerconnection_getstats.js
diff --git a/chrome/test/data/webrtc/peerconnection_getstats.js b/chrome/test/data/webrtc/peerconnection_getstats.js
index 9eea0b6e924bbbe8e6e04ef942f3361e6d84df7b..3bc2f1854bdfb1fb308490f8bd1375541c8c60e6 100644
--- a/chrome/test/data/webrtc/peerconnection_getstats.js
+++ b/chrome/test/data/webrtc/peerconnection_getstats.js
@@ -261,6 +261,29 @@ function verifyStatsGeneratedPromise() {
 }
 
 /**
+ * Gets the result of the promise-based |RTCPeerConnection.getStats| as a
+ * dictionary of RTCStats-dictionaries.
+ *
+ * Returns "ok-" followed by a JSON-stringified dictionary of dictionaries to
+ * the test.
+ */
+function getStatsAsDictionary() {
+  peerConnection_().getStats()
+    .then(function(report) {
+      if (report == null || report.size == 0)
+        throw new failTest('report is null or empty.');
+      let reportDictionary = {};
+      for (let stats of report.values()) {
+        reportDictionary[stats.id] = stats;
+      }
+      returnToTest('ok-' + JSON.stringify(reportDictionary, null, '  '));

[hbos_chromium, 2016/11/30 12:38:05]

nit: "null, '  '" does pretty indented JSON, I did this for debugging and forgot
about it, will remove params before landing for compact JSON.

+    },
+    function(e) {
+      throw failTest('Promise was rejected: ' + e);
+    });
+}
+
+/**
  * Returns a complete list of whitelisted "RTCStats.type" values as a
  * JSON-stringified array of strings to the test.
  */