Bug 1877242 - Use a FunctionRef in CanonicalBrowsingContext::CallOnAllTopDescendants. r=nika

This should be marginally more efficient, in theory, so do it drive-by.

Differential Revision: https://phabricator.services.mozilla.com/D199902

docshell/base/CanonicalBrowsingContext.cpp

@@ -818,8 +818,7 @@ RefPtr<PrintPromise> CanonicalBrowsingContext::Print(
 }
 
 void CanonicalBrowsingContext::CallOnAllTopDescendants(
-    const std::function<mozilla::CallState(CanonicalBrowsingContext*)>&
-        aCallback) {
+    const FunctionRef<CallState(CanonicalBrowsingContext*)>& aCallback) {
   MOZ_ASSERT(IsChrome(), "Should only call in chrome BC");
   MOZ_ASSERT(!GetParentCrossChromeBoundary(),
              "Should only call on top chrome BC");

docshell/base/CanonicalBrowsingContext.h

@@ -140,11 +140,9 @@ class CanonicalBrowsingContext final : public BrowsingContext {
                                                        ErrorResult&);
 
   // Call the given callback on all top-level descendant BrowsingContexts.
-  // Return Callstate::Stop from the callback to stop calling
-  // further children.
+  // Return Callstate::Stop from the callback to stop calling further children.
   void CallOnAllTopDescendants(
-      const std::function<mozilla::CallState(CanonicalBrowsingContext*)>&
-          aCallback);
+      const FunctionRef<CallState(CanonicalBrowsingContext*)>& aCallback);
 
   void SessionHistoryCommit(uint64_t aLoadId, const nsID& aChangeID,
                             uint32_t aLoadType, bool aPersist,