Avoid firing load events on style elements if there is no listeners for that

third_party/WebKit/Source/core/html/HTMLStyleElement.cpp

Index: third_party/WebKit/Source/core/html/HTMLStyleElement.cpp
diff --git a/third_party/WebKit/Source/core/html/HTMLStyleElement.cpp b/third_party/WebKit/Source/core/html/HTMLStyleElement.cpp
index 349287aed4bc887a2a296dfffab347247ad03620..c2ca8114c9bde6d76d3d923334f2a3bf2b04989a 100644
--- a/third_party/WebKit/Source/core/html/HTMLStyleElement.cpp
+++ b/third_party/WebKit/Source/core/html/HTMLStyleElement.cpp
@@ -107,9 +107,13 @@ const AtomicString& HTMLStyleElement::type() const {
 
 void HTMLStyleElement::DispatchPendingEvent(
     std::unique_ptr<IncrementLoadEventDelayCount> count) {
-  DispatchEvent(Event::Create(loaded_sheet_ ? EventTypeNames::load
-                                            : EventTypeNames::error));
-
+  if (loaded_sheet_) {
+    if (GetDocument().HasListenerType(
+            Document::LOAD_LISTENER_AT_CAPTURE_PHASE_OR_AT_STYLE_ELEMENT))
+      DispatchEvent(Event::Create(EventTypeNames::load));
+  } else {
+    DispatchEvent(Event::Create(EventTypeNames::error));
+  }
   // Checks Document's load event synchronously here for performance.
   // This is safe because dispatchPendingEvent() is called asynchronously.
   count->ClearAndCheckLoadEvent();