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

tracing/tracing/ui/tracks/global_memory_dump_track.html

Index: tracing/tracing/ui/tracks/global_memory_dump_track.html
diff --git a/tracing/tracing/ui/tracks/global_memory_dump_track.html b/tracing/tracing/ui/tracks/global_memory_dump_track.html
index 0e2e4d54c2467c5d187da26add0583c5723eed16..143957a86402e97799df0a3858b49c601a5c3215 100644
--- a/tracing/tracing/ui/tracks/global_memory_dump_track.html
+++ b/tracing/tracing/ui/tracks/global_memory_dump_track.html
@@ -63,7 +63,7 @@ tr.exportTo('tr.ui.tracks', function() {
       var track = new tr.ui.tracks.LetterDotTrack(this.viewport);
       track.heading = 'Memory Dumps';
       track.items = items;
-      this.appendChild(track);
+      Polymer.dom(this).appendChild(track);
     },
 
     appendUsedMemoryTrack_: function() {
@@ -77,7 +77,7 @@ tr.exportTo('tr.ui.tracks', function() {
       track.height = USED_MEMORY_TRACK_HEIGHT + 'px';
       track.series = series;
       track.autoSetAllAxes({expandMax: true});
-      this.appendChild(track);
+      Polymer.dom(this).appendChild(track);
     },
 
     appendAllocatedMemoryTrack_: function() {
@@ -91,7 +91,7 @@ tr.exportTo('tr.ui.tracks', function() {
       track.height = ALLOCATED_MEMORY_TRACK_HEIGHT + 'px';
       track.series = series;
       track.autoSetAllAxes({expandMax: true});
-      this.appendChild(track);
+      Polymer.dom(this).appendChild(track);
     }
   };