Bug 1587767 - Assert that link flag handling is correct, and that NodeInfoChanged is only called on disconnected nodes. r=smaug

Differential Revision: https://phabricator.services.mozilla.com/D48830

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

dom/base/Element.cpp

@@ -21,6 +21,7 @@
 #include "mozilla/dom/BindContext.h"
 #include "mozilla/dom/Flex.h"
 #include "mozilla/dom/Grid.h"
+#include "mozilla/dom/Link.h"
 #include "mozilla/dom/ScriptLoader.h"
 #include "mozilla/dom/Text.h"
 #include "mozilla/gfx/Matrix.h"
@@ -4380,5 +4381,14 @@ double Element::FirstLineBoxBSize() const {
              : 0.0;
 }
 
+#ifdef MOZ_DIAGNOSTIC_ASSERT_ENABLED
+void Element::AssertInvariantsOnNodeInfoChange() {
+  MOZ_DIAGNOSTIC_ASSERT(!IsInComposedDoc());
+  if (nsCOMPtr<Link> link = do_QueryInterface(this)) {
+    MOZ_DIAGNOSTIC_ASSERT(!link->HasPendingLinkUpdate());
+  }
+}
+#endif
+
 }  // namespace dom
 }  // namespace mozilla

dom/base/Element.h

@@ -1468,7 +1468,11 @@ class Element : public FragmentOrElement {
    *
    * If you change this, change also the similar method in Link.
    */
-  virtual void NodeInfoChanged(Document* aOldDoc) {}
+  virtual void NodeInfoChanged(Document* aOldDoc) {
+#ifdef MOZ_DIAGNOSTIC_ASSERT_ENABLED
+    AssertInvariantsOnNodeInfoChange();
+#endif
+  }
 
   /**
    * Parse a string into an nsAttrValue for a CORS attribute.  This
@@ -1917,6 +1921,10 @@ class Element : public FragmentOrElement {
                        ReparseAttributes = ReparseAttributes::Yes);
 
  private:
+#ifdef MOZ_DIAGNOSTIC_ASSERT_ENABLED
+  void AssertInvariantsOnNodeInfoChange();
+#endif
+
   /**
    * Slow path for GetClasses, this should only be called for SVG elements.
    */