Bug 1564208 part 2: Use Maybe<bool> to represent lazily-initialized bools for SVG/MathML enabling. r=smaug

This patch shouldn't affect behavior at all -- it's just removing a custom enum
type, in favor of our more standard representation for lazily-initialized bool,
which is Maybe<bool>.

Differential Revision: https://phabricator.services.mozilla.com/D37465

--HG--
extra : moz-landing-system : lando

dom/base/nsNodeInfoManager.cpp

@@ -46,9 +46,7 @@ nsNodeInfoManager::nsNodeInfoManager()
       mTextNodeInfo(nullptr),
       mCommentNodeInfo(nullptr),
       mDocumentNodeInfo(nullptr),
-      mRecentlyUsedNodeInfos(),
-      mSVGEnabled(eTriUnset),
-      mMathMLEnabled(eTriUnset) {
+      mRecentlyUsedNodeInfos() {
   nsLayoutStatics::AddRef();
 
   if (gNodeInfoManagerLeakPRLog)
@@ -352,7 +350,7 @@ bool nsNodeInfoManager::InternalSVGEnabled() {
              nsIContentPolicy::TYPE_OTHER) &&
         (IsSystemOrAddonPrincipal(loadInfo->LoadingPrincipal()) ||
          IsSystemOrAddonPrincipal(loadInfo->TriggeringPrincipal()))));
-  mSVGEnabled = conclusion ? eTriTrue : eTriFalse;
+  mSVGEnabled = Some(conclusion);
   return conclusion;
 }
 
@@ -362,7 +360,7 @@ bool nsNodeInfoManager::InternalMathMLEnabled() {
   nsNameSpaceManager* nsmgr = nsNameSpaceManager::GetInstance();
   bool conclusion = ((nsmgr && !nsmgr->mMathMLDisabled) ||
                      nsContentUtils::IsSystemPrincipal(mPrincipal));
-  mMathMLEnabled = conclusion ? eTriTrue : eTriFalse;
+  mMathMLEnabled = Some(conclusion);
   return conclusion;
 }
 

dom/base/nsNodeInfoManager.h

@@ -100,24 +100,16 @@ class nsNodeInfoManager final {
 
   nsBindingManager* GetBindingManager() const { return mBindingManager; }
 
-  enum Tri { eTriUnset = 0, eTriFalse, eTriTrue };
-
   /**
    * Returns true if SVG nodes in this document have real SVG semantics.
    */
-  bool SVGEnabled() {
-    return mSVGEnabled == eTriTrue
-               ? true
-               : mSVGEnabled == eTriFalse ? false : InternalSVGEnabled();
-  }
+  bool SVGEnabled() { return mSVGEnabled.valueOr(InternalSVGEnabled()); }
 
   /**
    * Returns true if MathML nodes in this document have real MathML semantics.
    */
   bool MathMLEnabled() {
-    return mMathMLEnabled == eTriTrue
-               ? true
-               : mMathMLEnabled == eTriFalse ? false : InternalMathMLEnabled();
+    return mMathMLEnabled.valueOr(InternalMathMLEnabled());
   }
 
   void AddSizeOfIncludingThis(nsWindowSizes& aSizes) const;
@@ -171,8 +163,8 @@ class nsNodeInfoManager final {
       mDocumentNodeInfo;  // WEAK to avoid circular ownership
   RefPtr<nsBindingManager> mBindingManager;
   NodeInfoCache mRecentlyUsedNodeInfos;
-  Tri mSVGEnabled;
-  Tri mMathMLEnabled;
+  mozilla::Maybe<bool> mSVGEnabled;     // Lazily initialized.
+  mozilla::Maybe<bool> mMathMLEnabled;  // Lazily initialized.
 };
 
 #endif /* nsNodeInfoManager_h___ */