Bug 1819767 - [devtools] Avoid instantiating EventCallbackDebuggerNot…

…ificationGuard when DevTools aren't opened at all. r=smaug Note that it may still be instantiated if DevTools are debugging another document/context. Enabling this codepath only if the related document is debugged by devtools would require checking BrowsingContext.isWatchedByDevTools. Differential Revision: https://phabricator.services.mozilla.com/D173439
iaxat · Mar 30, 2023 · 175040d · 175040d
1 parent db486d2
commit 175040d
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Showing 2 changed files with 7 additions and 3 deletions.
diff --git a/dom/debugger/EventCallbackDebuggerNotification.h b/dom/debugger/EventCallbackDebuggerNotification.h
@@ -51,7 +51,7 @@ class EventCallbackDebuggerNotification : public CallbackDebuggerNotification {
 
 class MOZ_RAII EventCallbackDebuggerNotificationGuard final {
  public:
-  MOZ_CAN_RUN_SCRIPT explicit EventCallbackDebuggerNotificationGuard(
+  MOZ_CAN_RUN_SCRIPT_BOUNDARY explicit EventCallbackDebuggerNotificationGuard(
       mozilla::dom::EventTarget* aEventTarget, mozilla::dom::Event* aEvent)
       : mDebuggeeGlobal(aEventTarget ? aEventTarget->GetOwnerGlobal()
                                      : nullptr),
@@ -68,7 +68,7 @@ class MOZ_RAII EventCallbackDebuggerNotificationGuard final {
   EventCallbackDebuggerNotificationGuard& operator=(
       EventCallbackDebuggerNotificationGuard&&) = delete;
 
-  MOZ_CAN_RUN_SCRIPT ~EventCallbackDebuggerNotificationGuard() {
+  MOZ_CAN_RUN_SCRIPT_BOUNDARY ~EventCallbackDebuggerNotificationGuard() {
     Dispatch(CallbackDebuggerNotificationPhase::Post);
   }
 

diff --git a/dom/events/EventListenerManager.cpp b/dom/events/EventListenerManager.cpp
@@ -36,6 +36,7 @@
 #include "mozilla/TimelineConsumers.h"
 #include "mozilla/EventTimelineMarker.h"
 #include "mozilla/TimeStamp.h"
+#include "mozilla/dom/ChromeUtils.h"
 
 #include "EventListenerService.h"
 #include "nsCOMPtr.h"
@@ -1299,7 +1300,10 @@ nsresult EventListenerManager::HandleEventSubType(Listener* aListener,
   }
 
   if (NS_SUCCEEDED(result)) {
-    EventCallbackDebuggerNotificationGuard dbgGuard(aCurrentTarget, aDOMEvent);
+    Maybe<EventCallbackDebuggerNotificationGuard> dbgGuard;
+    if (dom::ChromeUtils::IsDevToolsOpened()) {
+      dbgGuard.emplace(aCurrentTarget, aDOMEvent);
+    }
     nsAutoMicroTask mt;
 
     // Event::currentTarget is set in EventDispatcher.