1 files changed, 25 insertions, 3 deletions

diff --git a/dom/base/nsIDocument.h b/dom/base/nsIDocument.h
index 7a73fae71..d76a12d71 100644
--- a/dom/base/nsIDocument.h
+++ b/dom/base/nsIDocument.h
@@ -2260,21 +2260,27 @@ public:
    * nesting and possible sources, which are used to inform URL selection
    * responsive <picture> or <img srcset> images.  Unset attributes are expected
    * to be marked void.
+   * If this image is for <picture> or <img srcset>, aIsImgSet will be set to
+   * true, false otherwise.
    */
   virtual already_AddRefed<nsIURI>
     ResolvePreloadImage(nsIURI *aBaseURI,
                         const nsAString& aSrcAttr,
                         const nsAString& aSrcsetAttr,
-                        const nsAString& aSizesAttr) = 0;
+                        const nsAString& aSizesAttr,
+                        bool *aIsImgSet) = 0;
   /**
    * Called by nsParser to preload images. Can be removed and code moved
    * to nsPreloadURIs::PreloadURIs() in file nsParser.cpp whenever the
    * parser-module is linked with gklayout-module.  aCrossOriginAttr should
    * be a void string if the attr is not present.
+   * aIsImgSet is the value got from calling ResolvePreloadImage, it is true
+   * when this image is for loading <picture> or <img srcset> images.
    */
   virtual void MaybePreLoadImage(nsIURI* uri,
                                  const nsAString& aCrossOriginAttr,
-                                 ReferrerPolicyEnum aReferrerPolicy) = 0;
+                                 ReferrerPolicyEnum aReferrerPolicy,
+                                 bool aIsImgSet) = 0;
 
   /**
    * Called by images to forget an image preload when they start doing
@@ -3439,13 +3445,29 @@ nsINode::OwnerDocAsNode() const
   return OwnerDoc();
 }
 
+// ShouldUseXBLScope is defined here as a template so that we can get the faster
+// version of IsInAnonymousSubtree if we're statically known to be an
+// nsIContent.  we could try defining ShouldUseXBLScope separately on nsINode
+// and nsIContent, but then we couldn't put its nsINode implementation here
+// (because this header does not include nsIContent) and we can't put it in
+// nsIContent.h, because the definition of nsIContent::IsInAnonymousSubtree is
+// in nsIContentInlines.h.  And then we get include hell from people trying to
+// call nsINode::GetParentObject but not including nsIContentInlines.h and with
+// no really good way to include it.
+template<typename T>
+inline bool ShouldUseXBLScope(const T* aNode)
+{
+  return aNode->IsInAnonymousSubtree() &&
+         !aNode->IsAnonymousContentInSVGUseSubtree();
+}
+
 inline mozilla::dom::ParentObject
 nsINode::GetParentObject() const
 {
   mozilla::dom::ParentObject p(OwnerDoc());
     // Note that mUseXBLScope is a no-op for chrome, and other places where we
     // don't use XBL scopes.
-  p.mUseXBLScope = IsInAnonymousSubtree() && !IsAnonymousContentInSVGUseSubtree();
+  p.mUseXBLScope = ShouldUseXBLScope(this);
   return p;
 }