Bug 1685828 - Stop calling SVG and MathML enabling helpers every time we check their enabling status. r=emilio

Differential Revision: https://phabricator.services.mozilla.com/D101244

dom/base/nsNodeInfoManager.cpp

@@ -362,6 +362,8 @@ static bool IsSystemOrAddonOrAboutPrincipal(nsIPrincipal* aPrincipal) {
 }
 
 bool nsNodeInfoManager::InternalSVGEnabled() {
+  MOZ_ASSERT(!mSVGEnabled, "Caller should use the cached mSVGEnabled!");
+
   // If the svg.disabled pref. is true, convert all SVG nodes into
   // disabled SVG nodes by swapping the namespace.
   nsNameSpaceManager* nsmgr = nsNameSpaceManager::GetInstance();
@@ -396,6 +398,8 @@ bool nsNodeInfoManager::InternalSVGEnabled() {
 }
 
 bool nsNodeInfoManager::InternalMathMLEnabled() {
+  MOZ_ASSERT(!mMathMLEnabled, "Caller should use the cached mMathMLEnabled!");
+
   // If the mathml.disabled pref. is true, convert all MathML nodes into
   // disabled MathML nodes by swapping the namespace.
   nsNameSpaceManager* nsmgr = nsNameSpaceManager::GetInstance();

dom/base/nsNodeInfoManager.h

@@ -101,13 +101,16 @@ class nsNodeInfoManager final {
   /**
    * Returns true if SVG nodes in this document have real SVG semantics.
    */
-  bool SVGEnabled() { return mSVGEnabled.valueOr(InternalSVGEnabled()); }
+  bool SVGEnabled() {
+    return mSVGEnabled.valueOrFrom([this] { return InternalSVGEnabled(); });
+  }
 
   /**
    * Returns true if MathML nodes in this document have real MathML semantics.
    */
   bool MathMLEnabled() {
-    return mMathMLEnabled.valueOr(InternalMathMLEnabled());
+    return mMathMLEnabled.valueOrFrom(
+        [this] { return InternalMathMLEnabled(); });
   }
 
   mozilla::dom::DOMArena* GetArenaAllocator() { return mArena; }