DevTools: Capture async stacks for event listeners.

Source/core/inspector/InspectorInstrumentation.cpp

Index: Source/core/inspector/InspectorInstrumentation.cpp
diff --git a/Source/core/inspector/InspectorInstrumentation.cpp b/Source/core/inspector/InspectorInstrumentation.cpp
index bc982c73036bc89c49bfdfb00239c769f3de9729..9e5b7eb59b759e194845eb97989ad41a878ea187 100644
--- a/Source/core/inspector/InspectorInstrumentation.cpp
+++ b/Source/core/inspector/InspectorInstrumentation.cpp
@@ -31,6 +31,7 @@
 #include "config.h"
 #include "core/inspector/InspectorInstrumentation.h"
 
+#include "core/events/EventTarget.h"
 #include "core/fetch/FetchInitiatorInfo.h"
 #include "core/inspector/InspectorAgent.h"
 #include "core/inspector/InspectorCSSAgent.h"
@@ -206,6 +207,13 @@ InstrumentingAgents* instrumentingAgentsFor(Page* page)
     return instrumentationForPage(page);
 }
 
+InstrumentingAgents* instrumentingAgentsFor(EventTarget* eventTarget)
+{
+    if (!eventTarget)
+        return 0;
+    return instrumentingAgentsFor(eventTarget->executionContext());
+}
+
 InstrumentingAgents* instrumentingAgentsFor(RenderObject* renderer)
 {
     return instrumentingAgentsFor(renderer->frame());