Update gpu trace marker system for MultiDrawBuffer world

src/gpu/GrInOrderDrawBuffer.cpp

Index: src/gpu/GrInOrderDrawBuffer.cpp
diff --git a/src/gpu/GrInOrderDrawBuffer.cpp b/src/gpu/GrInOrderDrawBuffer.cpp
index 24db2e08dd83730a193372563ed95c80ef12693b..25846358020963fb762307b747a3c02fc644ef07 100644
--- a/src/gpu/GrInOrderDrawBuffer.cpp
+++ b/src/gpu/GrInOrderDrawBuffer.cpp
@@ -395,9 +395,9 @@ void GrInOrderDrawBuffer::recordTraceMarkersIfNecessary(GrTargetCommands::Cmd* c
     const GrTraceMarkerSet& activeTraceMarkers = this->getActiveTraceMarkers();
     if (activeTraceMarkers.count() > 0) {
         if (cmd->isTraced()) {
-            fGpuCmdMarkers.back().addSet(activeTraceMarkers);
+            fGpuCmdMarkers[cmd->markerID()].addSet(activeTraceMarkers);
         } else {
-            cmd->makeTraced();
+            cmd->setMarkerID(fGpuCmdMarkers.count());
             fGpuCmdMarkers.push_back(activeTraceMarkers);
         }
     }