Bug 1276438 part 1. Move the implementation of the .body getter from nsHTMLDocument to nsIDocument.

Tag UXP Issue #1344
Tag UXP Issue #252

dom/base/nsDocument.cpp

@@ -6536,6 +6536,26 @@ nsIDocument::GetHtmlChildElement(nsIAtom* aTag)
   return nullptr;
 }
 
+nsGenericHTMLElement*
+nsIDocument::GetBody()
+{
+  Element* html = GetHtmlElement();
+  if (!html) {
+    return nullptr;
+  }
+
+  for (nsIContent* child = html->GetFirstChild();
+       child;
+       child = child->GetNextSibling()) {
+    if (child->IsHTMLElement(nsGkAtoms::body) ||
+        child->IsHTMLElement(nsGkAtoms::frameset)) {
+      return static_cast<nsGenericHTMLElement*>(child);
+    }
+  }
+
+  return nullptr;
+}
+
 Element*
 nsDocument::GetTitleElement()
 {

dom/base/nsIDocument.h

@@ -61,6 +61,7 @@ class nsFrameLoader;
 class nsHTMLCSSStyleSheet;
 class nsHTMLDocument;
 class nsHTMLStyleSheet;
+class nsGenericHTMLElement;
 class nsIAtom;
 class nsIBFCacheEntry;
 class nsIChannel;
@@ -1036,6 +1037,9 @@ public:
   Element* GetHeadElement() {
     return GetHtmlChildElement(nsGkAtoms::head);
   }
+  // Get the "body" in the sense of document.body: The first <body> or
+  // <frameset> that's a child of a root <html>
+  nsGenericHTMLElement* GetBody();
 
   /**
    * Accessors to the collection of stylesheets owned by this document.

dom/html/nsHTMLDocument.cpp

@@ -1013,26 +1013,6 @@ nsHTMLDocument::SetDomain(const nsAString& aDomain, ErrorResult& rv)
   rv = NodePrincipal()->SetDomain(newURI);
 }
 
-nsGenericHTMLElement*
-nsHTMLDocument::GetBody()
-{
-  Element* html = GetHtmlElement();
-  if (!html) {
-    return nullptr;
-  }
-
-  for (nsIContent* child = html->GetFirstChild();
-       child;
-       child = child->GetNextSibling()) {
-    if (child->IsHTMLElement(nsGkAtoms::body) ||
-        child->IsHTMLElement(nsGkAtoms::frameset)) {
-      return static_cast<nsGenericHTMLElement*>(child);
-    }
-  }
-
-  return nullptr;
-}
-
 NS_IMETHODIMP
 nsHTMLDocument::GetBody(nsIDOMHTMLElement** aBody)
 {

dom/html/nsHTMLDocument.h

@@ -175,7 +175,7 @@ public:
                    JS::MutableHandle<JSObject*> aRetval,
                    mozilla::ErrorResult& rv);
   void GetSupportedNames(nsTArray<nsString>& aNames);
-  nsGenericHTMLElement *GetBody();
+  using nsIDocument::GetBody;
   void SetBody(nsGenericHTMLElement* aBody, mozilla::ErrorResult& rv);
   mozilla::dom::HTMLSharedElement *GetHead() {
     return static_cast<mozilla::dom::HTMLSharedElement*>(GetHeadElement());