Telemetry: make media perf tests log errors rather than timing out

tools/perf/metrics/media.js

Index: tools/perf/metrics/media.js
diff --git a/tools/perf/metrics/media.js b/tools/perf/metrics/media.js
index f2d466f615d282e8897ea46d95d5d2f15b23cd1c..4a1f6c7c3e0f33fbab92fc8c2f4463decc9aadd2 100644
--- a/tools/perf/metrics/media.js
+++ b/tools/perf/metrics/media.js
@@ -123,12 +123,17 @@
   };
 
   HTMLMediaMetric.prototype.getMetrics = function() {
-    this.metrics['decoded_frame_count'] = this.element.webkitDecodedFrameCount;
-    this.metrics['dropped_frame_count'] = this.element.webkitDroppedFrameCount;
+    var decodedFrames = this.element.webkitDecodedFrameCount;
+    var droppedFrames = this.element.webkitDroppedFrameCount;
+    // Audio media does not report decoded/dropped frame count
+    if (decodedFrames != undefined)
+      this.metrics['decoded_frame_count'] = decodedFrames;
+    if (droppedFrames != undefined)
+      this.metrics['dropped_frame_count'] = droppedFrames;
     this.metrics['decoded_video_bytes'] =
-        this.element.webkitVideoDecodedByteCount;
+        this.element.webkitVideoDecodedByteCount || 0;
     this.metrics['decoded_audio_bytes'] =
-        this.element.webkitAudioDecodedByteCount;
+        this.element.webkitAudioDecodedByteCount || 0;
     return this.metrics;
   };
 
@@ -157,10 +162,16 @@
   function checkElementIsNotBound(element) {
     if (!element)
       return;
+    if (getMediaMetric(element))
+      throw new Error('Can not create MediaMetric for same element twice.');
+  }
+
+  function getMediaMetric(element) {
     for (var i = 0; i < window.__mediaMetrics.length; i++) {
       if (window.__mediaMetrics[i].element == element)
-        throw new Error('Can not create MediaMetric for same element twice.');
+        return window.__mediaMetrics[i];
     }
+    return null;
   }
 
   function createMediaMetricsForDocument() {
@@ -192,6 +203,7 @@
 
   window.__globalCounter = 0;
   window.__mediaMetrics = [];
+  window.__getMediaMetric = getMediaMetric;
   window.__getAllMetrics = getAllMetrics;
   window.__createMediaMetricsForDocument = createMediaMetricsForDocument;
 })();