#442: M1347639

dom/base/nsGenConImageContent.cpp

@@ -56,6 +56,9 @@ class nsGenConImageContent final : public nsXMLElement,
     }
     return nsXMLElement::PreHandleEvent(aVisitor);
   }
+
+protected:
+  nsIContent* AsContent() override { return this; }
 
 private:
   virtual ~nsGenConImageContent();

dom/base/nsImageLoadingContent.cpp

@@ -868,7 +868,7 @@ nsImageLoadingContent::LoadImage(nsIURI* aNewURI,
   // We use the principal of aDocument to avoid having to QI |this| an extra
   // time. It should always be the same as the principal of this node.
 #ifdef DEBUG
-  nsCOMPtr<nsIContent> thisContent = do_QueryInterface(static_cast<nsIImageLoadingContent*>(this));
+  nsIContent* thisContent = AsContent();
   MOZ_ASSERT(thisContent &&
              thisContent->NodePrincipal() == aDocument->NodePrincipal(),
              "Principal mismatch?");
@@ -909,8 +909,7 @@ nsImageLoadingContent::LoadImage(nsIURI* aNewURI,
 
   // Not blocked. Do the load.
   RefPtr<imgRequestProxy>& req = PrepareNextRequest(aImageLoadType);
-  nsCOMPtr<nsIContent> content =
-      do_QueryInterface(static_cast<nsIImageLoadingContent*>(this));
+  nsIContent* content = AsContent();
   nsresult rv = nsContentUtils::LoadImage(aNewURI, aDocument,
                                           aDocument->NodePrincipal(),
                                           aDocument->GetDocumentURI(),
@@ -1048,10 +1047,7 @@ nsImageLoadingContent::UpdateImageState(bool aNotify)
     return;
   }
 
-  nsCOMPtr<nsIContent> thisContent = do_QueryInterface(static_cast<nsIImageLoadingContent*>(this));
-  if (!thisContent) {
-    return;
-  }
+  nsIContent* thisContent = AsContent();
 
   mLoading = mBroken = mUserDisabled = mSuppressed = false;
 
@@ -1115,29 +1111,19 @@ nsImageLoadingContent::UseAsPrimaryRequest(imgRequestProxy* aRequest,
 nsIDocument*
 nsImageLoadingContent::GetOurOwnerDoc()
 {
-  nsCOMPtr<nsIContent> thisContent =
-    do_QueryInterface(static_cast<nsIImageLoadingContent*>(this));
-  NS_ENSURE_TRUE(thisContent, nullptr);
-
-  return thisContent->OwnerDoc();
+  return AsContent()->OwnerDoc();
 }
 
 nsIDocument*
 nsImageLoadingContent::GetOurCurrentDoc()
 {
-  nsCOMPtr<nsIContent> thisContent =
-    do_QueryInterface(static_cast<nsIImageLoadingContent*>(this));
-  NS_ENSURE_TRUE(thisContent, nullptr);
-
-  return thisContent->GetComposedDoc();
+  return AsContent()->GetComposedDoc();
 }
 
 nsIFrame*
 nsImageLoadingContent::GetOurPrimaryFrame()
 {
-  nsCOMPtr<nsIContent> thisContent =
-    do_QueryInterface(static_cast<nsIImageLoadingContent*>(this));
-  return thisContent->GetPrimaryFrame();
+  return AsContent()->GetPrimaryFrame();
 }
 
 nsPresContext* nsImageLoadingContent::GetFramePresContext()
@@ -1159,8 +1145,7 @@ nsImageLoadingContent::StringToURI(const nsAString& aSpec,
   NS_PRECONDITION(aURI, "Null out param");
 
   // (1) Get the base URI
-  nsCOMPtr<nsIContent> thisContent = do_QueryInterface(static_cast<nsIImageLoadingContent*>(this));
-  NS_ASSERTION(thisContent, "An image loading content must be an nsIContent");
+  nsIContent* thisContent = AsContent();
   nsCOMPtr<nsIURI> baseURL = thisContent->GetBaseURI();
 
   // (2) Get the charset

dom/base/nsImageLoadingContent.h

@@ -214,6 +214,10 @@ class nsImageLoadingContent : public nsIImageLoadingContent,
   // The nsContentPolicyType we would use for this ImageLoadType
   static nsContentPolicyType PolicyTypeForLoad(ImageLoadType aImageLoadType);
 
+  // Get ourselves as an nsIContent*.  Not const because some of the callers
+  // want a non-const nsIContent.
+  virtual nsIContent* AsContent() = 0;
+
 private:
   /**
    * Struct used to manage the image observers.

dom/html/HTMLImageElement.h

@@ -350,6 +350,9 @@ class HTMLImageElement final : public nsGenericHTMLElement,
   virtual nsresult AfterSetAttr(int32_t aNameSpaceID, nsIAtom* aName,
                                 const nsAttrValue* aValue, bool aNotify) override;
 
+  // Override for nsImageLoadingContent.
+  nsIContent* AsContent() override { return this; }
+
   // This is a weak reference that this element and the HTMLFormElement
   // cooperate in maintaining.
   HTMLFormElement* mForm;

dom/html/HTMLInputElement.h

@@ -1254,6 +1254,11 @@ class HTMLInputElement final : public nsGenericHTMLFormElementWithState,
    */
   bool IsPopupBlocked() const;
 
+  /**
+   * Override for nsImageLoadingContent.
+   */
+  nsIContent* AsContent() override { return this; }
+
   nsCOMPtr<nsIControllers> mControllers;
 
   /*

dom/html/HTMLObjectElement.h

@@ -235,6 +235,10 @@ class HTMLObjectElement final : public nsGenericHTMLFormElement
     return GetContentDocument();
   }
 
+protected:
+  // Override for nsImageLoadingContent.
+  nsIContent* AsContent() override { return this; }
+
 private:
   /**
    * Calls LoadObject with the correct arguments to start the plugin load.

dom/html/HTMLSharedObjectElement.h

@@ -192,6 +192,10 @@ class HTMLSharedObjectElement final : public nsGenericHTMLElement
     return GetContentDocument();
   }
 
+protected:
+  // Override for nsImageLoadingContent.
+  nsIContent* AsContent() override { return this; }
+
 private:
   virtual ~HTMLSharedObjectElement();
 

dom/svg/SVGFEImageElement.h

@@ -82,6 +82,9 @@ class SVGFEImageElement final : public SVGFEImageElementBase,
   virtual SVGAnimatedPreserveAspectRatio *GetPreserveAspectRatio() override;
   virtual StringAttributesInfo GetStringInfo() override;
 
+  // Override for nsImageLoadingContent.
+  nsIContent* AsContent() override { return this; }
+
   enum { RESULT, HREF };
   nsSVGString mStringAttributes[2];
   static StringInfo sStringInfo[2];

dom/svg/SVGImageElement.h

@@ -83,6 +83,9 @@ class SVGImageElement : public SVGImageElementBase,
   virtual SVGAnimatedPreserveAspectRatio *GetPreserveAspectRatio() override;
   virtual StringAttributesInfo GetStringInfo() override;
 
+  // Override for nsImageLoadingContent.
+  nsIContent* AsContent() override { return this; }
+
   enum { ATTR_X, ATTR_Y, ATTR_WIDTH, ATTR_HEIGHT };
   nsSVGLength2 mLengthAttributes[4];
   static LengthInfo sLengthInfo[4];