Bug 1253788 - Don't reload inline chrome:// style sheets in nsXBLProt…

…otypeResources. r=bzbarsky

chrome/nsChromeRegistry.cpp

@@ -444,11 +444,13 @@ nsresult nsChromeRegistry::RefreshWindow(nsPIDOMWindowOuter* aWindow)
   }
 
   // Iterate over our old sheets and kick off a sync load of the new
-  // sheet if and only if it's a chrome URL.
+  // sheet if and only if it's a non-inline sheet with a chrome URL.
   for (StyleSheetHandle sheet : oldSheets) {
-    nsIURI* uri = sheet ? sheet->GetOriginalURI() : nullptr;
+    MOZ_ASSERT(sheet, "GetStyleSheetAt shouldn't return nullptr for "
+                      "in-range sheet indexes");
+    nsIURI* uri = sheet->GetSheetURI();
 
-    if (uri && IsChromeURI(uri)) {
+    if (!sheet->IsInline() && IsChromeURI(uri)) {
       // Reload the sheet.
       StyleSheetHandle::RefPtr newSheet;
       // XXX what about chrome sheets that have a title or are disabled?  This

dom/base/nsStyleLinkElement.cpp

@@ -219,7 +219,7 @@ nsStyleLinkElement::UpdateStyleSheet(nsICSSLoaderObserver* aObserver,
     nsCOMPtr<nsIDocument> doc = thisContent->IsInShadowTree() ?
       thisContent->OwnerDoc() : thisContent->GetUncomposedDoc();
     if (doc && doc->CSSLoader()->GetEnabled() &&
-        mStyleSheet && mStyleSheet->GetOriginalURI()) {
+        mStyleSheet && !mStyleSheet->IsInline()) {
       doc->CSSLoader()->ObsoleteSheet(mStyleSheet->GetOriginalURI());
     }
   }

dom/xbl/nsXBLPrototypeResources.cpp

@@ -80,7 +80,9 @@ nsXBLPrototypeResources::FlushSkinSheets()
 
   // We have scoped stylesheets.  Reload any chrome stylesheets we
   // encounter.  (If they aren't skin sheets, it doesn't matter, since
-  // they'll still be in the chrome cache.
+  // they'll still be in the chrome cache.  Skip inline sheets, which
+  // skin sheets can't be, and which in any case don't have a usable
+  // URL to reload.)
 
   nsTArray<StyleSheetHandle::RefPtr> oldSheets;
 
@@ -94,7 +96,7 @@ nsXBLPrototypeResources::FlushSkinSheets()
     nsIURI* uri = oldSheet->GetSheetURI();
 
     StyleSheetHandle::RefPtr newSheet;
-    if (IsChromeURI(uri)) {
+    if (!oldSheet->IsInline() && IsChromeURI(uri)) {
       if (NS_FAILED(cssLoader->LoadSheetSync(uri, &newSheet)))
         continue;
     }

layout/style/CSSStyleSheet.h

@@ -225,6 +225,9 @@ class CSSStyleSheet final : public nsIDOMCSSStyleSheet,
      return null */
   nsIURI* GetOriginalURI() const { return mInner->mOriginalSheetURI; }
 
+  // Whether the sheet is for an inline <style> element.
+  bool IsInline() const { return mInner->IsInline(); }
+
   // nsICSSLoaderObserver interface
   NS_IMETHOD StyleSheetLoaded(StyleSheetHandle aSheet, bool aWasAlternate,
                               nsresult aStatus) override;

layout/style/StyleSheetHandle.h

@@ -104,6 +104,7 @@ class StyleSheetHandle
     // CSSStyleSheet or ServoStyleSheet.  See corresponding comments in
     // CSSStyleSheet.h for descriptions of these methods.
 
+    inline bool IsInline() const;
     inline nsIURI* GetSheetURI() const;
     inline nsIURI* GetOriginalURI() const;
     inline nsIURI* GetBaseURI() const;

layout/style/StyleSheetHandleInlines.h

@@ -48,6 +48,12 @@ StyleSheetHandle::Ptr::Release()
   FORWARD(Release, ());
 }
 
+bool
+StyleSheetHandle::Ptr::IsInline() const
+{
+  FORWARD(IsInline, ());
+}
+
 nsIURI*
 StyleSheetHandle::Ptr::GetSheetURI() const
 {

layout/style/StyleSheetInfo.h

@@ -40,6 +40,9 @@ class StyleSheetInfo
   nsIURI* GetBaseURI() const { return mBaseURI; }
   void SetURIs(nsIURI* aSheetURI, nsIURI* aOriginalSheetURI, nsIURI* aBaseURI);
 
+  // Whether the sheet is for an inline <style> element.
+  bool IsInline() const { return !mOriginalSheetURI; }
+
   nsIPrincipal* Principal() const { return mPrincipal; }
   void SetPrincipal(nsIPrincipal* aPrincipal);