Cleanup DocumentXSLT construction

Change-Id: If76acf50bb70df341c88164961912b74b0c3bb31
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2341818Reviewed-by: Kentaro Hara <haraken@chromium.org>
Commit-Queue: Nate Chapin <japhet@chromium.org>
Cr-Commit-Position: refs/heads/master@{#795718}

third_party/blink/renderer/core/loader/document_loader.cc

@@ -1818,10 +1818,8 @@ void DocumentLoader::CommitNavigation() {
     document->SetBaseURLOverride(archive_->MainResource()->Url());
   }
 
-  if (commit_reason_ == CommitReason::kXSLT) {
-    DocumentXSLT::From(*document).SetTransformSourceDocument(
-        previous_window->document());
-  }
+  if (commit_reason_ == CommitReason::kXSLT)
+    DocumentXSLT::SetHasTransformSource(*document);
 
   DidInstallNewDocument(document);
 

third_party/blink/renderer/core/xml/document_xslt.cc

@@ -67,7 +67,7 @@ class DOMContentLoadedListener final
 };
 
 DocumentXSLT::DocumentXSLT(Document& document)
-    : Supplement<Document>(document), transform_source_document_(nullptr) {}
+    : Supplement<Document>(document) {}
 
 void DocumentXSLT::ApplyXSLTransform(Document& document,
                                      ProcessingInstruction* pi) {
@@ -154,17 +154,13 @@ bool DocumentXSLT::HasTransformSourceDocument(Document& document) {
   return Supplement<Document>::From<DocumentXSLT>(document);
 }
 
-DocumentXSLT& DocumentXSLT::From(Document& document) {
-  DocumentXSLT* supplement = Supplement<Document>::From<DocumentXSLT>(document);
-  if (!supplement) {
-    supplement = MakeGarbageCollected<DocumentXSLT>(document);
-    Supplement<Document>::ProvideTo(document, supplement);
-  }
-  return *supplement;
+void DocumentXSLT::SetHasTransformSource(Document& document) {
+  DCHECK(!HasTransformSourceDocument(document));
+  Supplement<Document>::ProvideTo(document,
+                                  MakeGarbageCollected<DocumentXSLT>(document));
 }
 
 void DocumentXSLT::Trace(Visitor* visitor) const {
-  visitor->Trace(transform_source_document_);
   Supplement<Document>::Trace(visitor);
 }
 

third_party/blink/renderer/core/xml/document_xslt.h

@@ -20,16 +20,7 @@ class DocumentXSLT final : public GarbageCollected<DocumentXSLT>,
  public:
   static const char kSupplementName[];
 
-  Document* TransformSourceDocument() {
-    return transform_source_document_.Get();
-  }
-
-  void SetTransformSourceDocument(Document* document) {
-    DCHECK(document);
-    transform_source_document_ = document;
-  }
-
-  static DocumentXSLT& From(Document&);
+  static void SetHasTransformSource(Document&);
 
   // The following static methods don't use any instance of DocumentXSLT.
   // They are just using DocumentXSLT namespace.
@@ -46,7 +37,6 @@ class DocumentXSLT final : public GarbageCollected<DocumentXSLT>,
   void Trace(Visitor*) const override;
 
  private:
-  Member<Document> transform_source_document_;
   DISALLOW_COPY_AND_ASSIGN(DocumentXSLT);
 };