Bug 1603534 - Merge ShadowRoot::StyleSheets and Document::StyleSheets(). r=nordzilla

They do the same so no reason to have it duplicated. EnsureDOMStyleSheets
doesn't have any other caller so just inline it there.

Differential Revision: https://phabricator.services.mozilla.com/D56986

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

dom/base/Document.h

@@ -1994,10 +1994,6 @@ class Document : public nsINode,
    * Style sheets are ordered, most significant last.
    */
 
-  StyleSheetList* StyleSheets() {
-    return &DocumentOrShadowRoot::EnsureDOMStyleSheets();
-  }
-
   void InsertSheetAt(size_t aIndex, StyleSheet&);
 
   /**

dom/base/DocumentOrShadowRoot.cpp

@@ -64,11 +64,11 @@ DocumentOrShadowRoot::~DocumentOrShadowRoot() {
   }
 }
 
-StyleSheetList& DocumentOrShadowRoot::EnsureDOMStyleSheets() {
+StyleSheetList* DocumentOrShadowRoot::StyleSheets() {
   if (!mDOMStyleSheets) {
     mDOMStyleSheets = new StyleSheetList(*this);
   }
-  return *mDOMStyleSheets;
+  return mDOMStyleSheets;
 }
 
 void DocumentOrShadowRoot::InsertSheetAt(size_t aIndex, StyleSheet& aSheet) {

dom/base/DocumentOrShadowRoot.h

@@ -22,6 +22,7 @@ class nsWindowSizes;
 
 namespace mozilla {
 class StyleSheet;
+class ErrorResult;
 
 namespace dom {
 
@@ -72,7 +73,7 @@ class DocumentOrShadowRoot {
     return mStyleSheets.IndexOf(&aSheet);
   }
 
-  StyleSheetList& EnsureDOMStyleSheets();
+  StyleSheetList* StyleSheets();
 
   Element* GetElementById(const nsAString& aElementId);
 

dom/base/ShadowRoot.h

@@ -80,10 +80,6 @@ class ShadowRoot final : public DocumentFragment,
   void SheetCloned(StyleSheet&);
   void StyleSheetApplicableStateChanged(StyleSheet&, bool aApplicable);
 
-  StyleSheetList* StyleSheets() {
-    return &DocumentOrShadowRoot::EnsureDOMStyleSheets();
-  }
-
   /**
    * Clones internal state, for example stylesheets, of aOther to 'this'.
    */