From cd6be07458e0f1e5191323ff4b2d578638aafe1e Mon Sep 17 00:00:00 2001
From: wuggy <ownedbywuigi@gmail.com>
Date: Fri, 7 Aug 2026 13:13:43 -0700
Subject: [PATCH] Revert "Optimise WebExtension implementaion pt.1"

This reverts commit 3be08bc94bf666c81d7b30c0ba042517169e5e6f.
---
 dom/base/CustomElementRegistry.cpp |  3 ---
 dom/base/CustomElementRegistry.h   |  7 +------
 dom/base/ShadowRoot.cpp            | 31 +++++++++++++++++-------------
 3 files changed, 19 insertions(+), 22 deletions(-)

diff --git a/dom/base/CustomElementRegistry.cpp b/dom/base/CustomElementRegistry.cpp
index bb10f3ca80..11ba39a67e 100644
--- a/dom/base/CustomElementRegistry.cpp
+++ b/dom/base/CustomElementRegistry.cpp
@@ -1278,9 +1278,6 @@ CustomElementDefinition::CustomElementDefinition(nsIAtom* aType,
     mCallbacks(aCallbacks),
     mDocOrder(aDocOrder)
 {
-  for (uint32_t i = 0; i < mObservedAttributes.Length(); ++i) {
-    mObservedAttributesSet.PutEntry(mObservedAttributes[i]);
-  }
 }
 
 //-----------------------------------------------------
diff --git a/dom/base/CustomElementRegistry.h b/dom/base/CustomElementRegistry.h
index 53f58b5a9f..06e5947dbc 100644
--- a/dom/base/CustomElementRegistry.h
+++ b/dom/base/CustomElementRegistry.h
@@ -16,8 +16,6 @@
 #include "mozilla/dom/WebComponentsBinding.h"
 #include "nsCycleCollectionParticipant.h"
 #include "nsGenericHTMLElement.h"
-#include "nsHashKeys.h"
-#include "nsTHashtable.h"
 #include "nsWrapperCache.h"
 
 class nsDocument;
@@ -168,9 +166,6 @@ struct CustomElementDefinition
   // The list of attributes that this custom element observes.
   nsCOMArray<nsIAtom> mObservedAttributes;
 
-  // Hash set for O(1) lookup of observed attributes.
-  nsTHashtable<nsISupportsHashKey> mObservedAttributesSet;
-
   // The prototype to use for new custom elements of this type.
   JS::Heap<JSObject *> mPrototype;
 
@@ -194,7 +189,7 @@ struct CustomElementDefinition
       return false;
     }
 
-    return mObservedAttributesSet.Contains(aName);
+    return mObservedAttributes.Contains(aName);
   }
 
 private:
diff --git a/dom/base/ShadowRoot.cpp b/dom/base/ShadowRoot.cpp
index d2da59edbb..f2ae953a0e 100644
--- a/dom/base/ShadowRoot.cpp
+++ b/dom/base/ShadowRoot.cpp
@@ -136,7 +136,7 @@ ShadowRoot::AddSlot(HTMLSlotElement* aSlot)
   MOZ_ASSERT(aSlot);
 
   // Note that if name attribute missing, the slot is a default slot.
-  nsAutoString name;
+ nsAutoString name;
   aSlot->GetName(name);
 
   nsTArray<HTMLSlotElement*>* currentSlots = mSlotMap.LookupOrAdd(name);
@@ -162,14 +162,25 @@ ShadowRoot::AddSlot(HTMLSlotElement* aSlot)
 
       oldSlot->RemoveAssignedNode(assignedNode);
       currentSlot->AppendAssignedNode(assignedNode);
+
+      Element* restyleElement;
+      if (assignedNode->IsElement()) {
+        restyleElement = assignedNode->AsElement();
+      } else {
+        // This is likely a text node. Use the host instead.
+        restyleElement = GetHost();
+      }
+      if (restyleElement) {
+        nsLayoutUtils::PostRestyleEvent(
+          restyleElement, eRestyle_Subtree, nsChangeHint(0));
+      }
+
       doEnqueueSlotChange = true;
     }
 
     if (doEnqueueSlotChange) {
       oldSlot->EnqueueSlotChangeEvent();
       currentSlot->EnqueueSlotChangeEvent();
-      nsLayoutUtils::PostRestyleEvent(
-        GetHost(), eRestyle_Subtree, nsChangeHint(0));
     }
   } else {
     // Otherwise add appropriate nodes to this slot from the host.
@@ -464,10 +475,7 @@ ShadowRoot::MaybeReassignElement(Element* aElement,
 void
 ShadowRoot::DistributionChanged()
 {
-  if (mSlotMap.IsEmpty()) {
-    return;
-  }
-
+  // FIXME(emilio): We could be more granular in a bunch of cases.
   auto* host = GetHost();
   if (!host || !host->IsInComposedDoc()) {
     return;
@@ -543,11 +551,8 @@ ShadowRoot::AttributeChanged(nsIDocument* aDocument,
     return;
   }
 
-  if (aElement->GetPrimaryFrame()) {
-    shell->DestroyFramesForAndRestyle(aElement);
-  } else {
-    nsLayoutUtils::PostRestyleEvent(aElement, eRestyle_Subtree, nsChangeHint(0));
-  }
+  //XXX optimize this!
+  shell->DestroyFramesForAndRestyle(aElement);
 }
 
 void
@@ -559,7 +564,7 @@ ShadowRoot::ContentAppended(nsIDocument* aDocument,
   for (nsIContent* content = aFirstNewContent;
        content;
        content = content->GetNextSibling()) {
-    ContentInserted(aDocument, aContainer, content, aNewIndexInContainer);
+    ContentInserted(aDocument, aContainer, aFirstNewContent, aNewIndexInContainer);
   }
 }