Add tracing to custom elements operations

third_party/WebKit/Source/core/dom/custom/CustomElementRegistry.cpp

Index: third_party/WebKit/Source/core/dom/custom/CustomElementRegistry.cpp
diff --git a/third_party/WebKit/Source/core/dom/custom/CustomElementRegistry.cpp b/third_party/WebKit/Source/core/dom/custom/CustomElementRegistry.cpp
index f500fb450624f32344001a292cbb9db57cf147ec..66919fd57022330f1273dcdb54ce5fa035f86615 100644
--- a/third_party/WebKit/Source/core/dom/custom/CustomElementRegistry.cpp
+++ b/third_party/WebKit/Source/core/dom/custom/CustomElementRegistry.cpp
@@ -22,6 +22,7 @@
 #include "core/dom/custom/CustomElementUpgradeSorter.h"
 #include "core/dom/custom/V0CustomElementRegistrationContext.h"
 #include "core/frame/LocalDOMWindow.h"
+#include "platform/tracing/TraceEvent.h"
 #include "wtf/Allocator.h"
 
 namespace blink {
@@ -104,6 +105,7 @@ void CustomElementRegistry::define(const AtomicString& name,
                                    CustomElementDefinitionBuilder& builder,
                                    const ElementDefinitionOptions& options,
                                    ExceptionState& exceptionState) {
+  TRACE_EVENT1("blink", "CustomElementRegistry::define", "name", name.utf8());
   if (!builder.checkConstructorIntrinsics())
     return;