[polymer] Replaces this.appendChild with Polymer.dom(this).appendChild

tracing/tracing/ui/tracks/model_track.html

Index: tracing/tracing/ui/tracks/model_track.html
diff --git a/tracing/tracing/ui/tracks/model_track.html b/tracing/tracing/ui/tracks/model_track.html
index 2405ea13a82cb0dc0c7e794d6df27d89a03a0a1a..ff5f12dcb7fbeae11080fe493a24d5ddb9de66e9 100644
--- a/tracing/tracing/ui/tracks/model_track.html
+++ b/tracing/tracing/ui/tracks/model_track.html
@@ -102,19 +102,19 @@ tr.exportTo('tr.ui.tracks', function() {
       if (this.model_.userModel.expectations.length) {
         var mrt = new tr.ui.tracks.InteractionTrack(this.viewport_);
         mrt.model = this.model_;
-        this.appendChild(mrt);
+        Polymer.dom(this).appendChild(mrt);
       }
 
       if (this.model_.alerts.length) {
         var at = new tr.ui.tracks.AlertTrack(this.viewport_);
         at.alerts = this.model_.alerts;
-        this.appendChild(at);
+        Polymer.dom(this).appendChild(at);
       }
 
       if (this.model_.globalMemoryDumps.length) {
         var gmdt = new tr.ui.tracks.GlobalMemoryDumpTrack(this.viewport_);
         gmdt.memoryDumps = this.model_.globalMemoryDumps;
-        this.appendChild(gmdt);
+        Polymer.dom(this).appendChild(gmdt);
       }
 
       this.appendDeviceTrack_();
@@ -132,7 +132,7 @@ tr.exportTo('tr.ui.tracks', function() {
         if (!track.hasVisibleContent)
           continue;
 
-        this.appendChild(track);
+        Polymer.dom(this).appendChild(track);
       }
       this.viewport_.rebuildEventToTrackMap();
       this.viewport_.rebuildContainerToTrackMap();
@@ -177,7 +177,7 @@ tr.exportTo('tr.ui.tracks', function() {
       track.device = this.model.device;
       if (!track.hasVisibleContent)
         return;
-      this.appendChild(track);
+      Polymer.dom(this).appendChild(track);
     },
 
     appendKernelTrack_: function() {
@@ -186,7 +186,7 @@ tr.exportTo('tr.ui.tracks', function() {
       track.kernel = this.model.kernel;
       if (!track.hasVisibleContent)
         return;
-      this.appendChild(track);
+      Polymer.dom(this).appendChild(track);
     },
 
     drawTrack: function(type) {