Bug 1492326, use Element helper methods in dom/layout instead of QueryInterface to get interface implementations that might be implemented by custom elements, r=paolo

dom/base/nsFocusManager.cpp

@@ -337,7 +337,8 @@ Element* nsFocusManager::GetRedirectedFocus(nsIContent* aContent) {
       return aContent->OwnerDoc()->GetAnonymousElementByAttribute(
           aContent, nsGkAtoms::anonid, NS_LITERAL_STRING("input"));
     } else {
-      nsCOMPtr<nsIDOMXULMenuListElement> menulist = do_QueryInterface(aContent);
+      nsCOMPtr<nsIDOMXULMenuListElement> menulist =
+          aContent->AsElement()->AsXULMenuList();
       if (menulist) {
         RefPtr<Element> inputField;
         menulist->GetInputField(getter_AddRefs(inputField));

dom/base/nsGlobalWindowInner.cpp

@@ -6799,8 +6799,7 @@ void nsGlobalWindowInner::NotifyDefaultButtonLoaded(Element& aDefaultButton,
                                                     ErrorResult& aError) {
 #ifdef MOZ_XUL
   // Don't snap to a disabled button.
-  nsCOMPtr<nsIDOMXULControlElement> xulControl =
-      do_QueryInterface(&aDefaultButton);
+  nsCOMPtr<nsIDOMXULControlElement> xulControl = aDefaultButton.AsXULControl();
   if (!xulControl) {
     aError.Throw(NS_ERROR_FAILURE);
     return;

dom/base/nsGlobalWindowOuter.cpp

@@ -162,10 +162,6 @@
 #include "nsIXULWindow.h"
 #include "nsITimedChannel.h"
 #include "nsServiceManagerUtils.h"
-#ifdef MOZ_XUL
-#include "nsIDOMXULControlElement.h"
-#include "nsMenuPopupFrame.h"
-#endif
 #include "mozilla/dom/CustomEvent.h"
 #include "nsIJARChannel.h"
 #include "nsIScreenManager.h"

dom/events/EventStateManager.cpp

@@ -945,7 +945,8 @@ static bool IsAccessKeyTarget(nsIContent* aContent, nsIFrame* aFrame,
   if (!aFrame->IsVisibleConsideringAncestors()) return false;
 
   // XUL controls can be activated.
-  nsCOMPtr<nsIDOMXULControlElement> control(do_QueryInterface(aContent));
+  nsCOMPtr<nsIDOMXULControlElement> control =
+      aContent->AsElement()->AsXULControl();
   if (control) return true;
 
   // HTML area, label and legend elements are never focusable, so
@@ -3017,15 +3018,15 @@ nsresult EventStateManager::PostHandleEvent(nsPresContext* aPresContext,
           // an anonymous node of the targeted element.
           suppressBlur = (ui->mUserFocus == StyleUserFocus::Ignore);
 
+          nsCOMPtr<Element> element = do_QueryInterface(aEvent->mTarget);
           if (!suppressBlur) {
-            nsCOMPtr<Element> element = do_QueryInterface(aEvent->mTarget);
             suppressBlur =
                 element && element->State().HasState(NS_EVENT_STATE_DISABLED);
           }
 
-          if (!suppressBlur) {
+          if (!suppressBlur && element) {
             nsCOMPtr<nsIDOMXULControlElement> xulControl =
-                do_QueryInterface(aEvent->mTarget);
+                element->AsXULControl();
             if (xulControl) {
               bool disabled;
               xulControl->GetDisabled(&disabled);

dom/xul/nsXULElement.cpp

@@ -437,7 +437,7 @@ bool nsXULElement::IsFocusableInternal(int32_t* aTabIndex, bool aWithMouse) {
   }
 #endif
 
-  nsCOMPtr<nsIDOMXULControlElement> xulControl = do_QueryObject(this);
+  nsCOMPtr<nsIDOMXULControlElement> xulControl = AsXULControl();
   if (xulControl) {
     // a disabled element cannot be focused and is not part of the tab order
     bool disabled;
@@ -543,8 +543,8 @@ bool nsXULElement::PerformAccesskey(bool aKeyCausesActivation,
         nsCOMPtr<Element> elementToFocus;
         // for radio buttons, focus the radiogroup instead
         if (content->IsXULElement(nsGkAtoms::radio)) {
-          nsCOMPtr<nsIDOMXULSelectControlItemElement> controlItem(
-              do_QueryInterface(content));
+          nsCOMPtr<nsIDOMXULSelectControlItemElement> controlItem =
+              content->AsXULSelectControlItem();
           if (controlItem) {
             bool disabled;
             controlItem->GetDisabled(&disabled);

layout/base/PresShell.cpp

@@ -7899,7 +7899,7 @@ void PresShell::GetCurrentItemAndPositionForElement(
   // as is.
   nsCOMPtr<Element> item;
   nsCOMPtr<nsIDOMXULMultiSelectControlElement> multiSelect =
-      do_QueryInterface(aFocusedElement);
+      aFocusedElement->AsXULMultiSelectControl();
   if (multiSelect) {
     checkLineHeight = false;
 
@@ -7946,10 +7946,10 @@ void PresShell::GetCurrentItemAndPositionForElement(
   } else {
     // don't check menulists as the selected item will be inside a popup.
     nsCOMPtr<nsIDOMXULMenuListElement> menulist =
-        do_QueryInterface(aFocusedElement);
+        aFocusedElement->AsXULMenuList();
     if (!menulist) {
       nsCOMPtr<nsIDOMXULSelectControlElement> select =
-          do_QueryInterface(aFocusedElement);
+          aFocusedElement->AsXULSelectControl();
       if (select) {
         checkLineHeight = false;
         select->GetSelectedItem(getter_AddRefs(item));

layout/xul/nsButtonBoxFrame.cpp

@@ -123,8 +123,9 @@ nsresult nsButtonBoxFrame::HandleEvent(nsPresContext* aPresContext,
         break;
       }
       if (NS_VK_RETURN == keyEvent->mKeyCode) {
-        nsCOMPtr<nsIDOMXULButtonElement> buttonEl(do_QueryInterface(mContent));
-        if (buttonEl) {
+        RefPtr<nsIDOMXULButtonElement> button =
+            mContent->AsElement()->AsXULButton();
+        if (button) {
           MouseClicked(aEvent);
           *aEventStatus = nsEventStatus_eConsumeNoDefault;
         }

layout/xul/nsMenuPopupFrame.cpp

@@ -1107,11 +1107,14 @@ nsPoint nsMenuPopupFrame::AdjustPositionForAnchorAlign(nsRect& anchorRect,
 nsIFrame* nsMenuPopupFrame::GetSelectedItemForAlignment() {
   // This method adjusts a menulist's popup such that the selected item is under
   // the cursor, aligned with the menulist label.
-  nsCOMPtr<nsIDOMXULSelectControlElement> select =
-      do_QueryInterface(mAnchorContent);
+  nsCOMPtr<nsIDOMXULSelectControlElement> select;
+  if (mAnchorContent) {
+    select = mAnchorContent->AsElement()->AsXULSelectControl();
+  }
+
   if (!select) {
     // If there isn't an anchor, then try just getting the parent of the popup.
-    select = do_QueryInterface(mContent->GetParent());
+    select = mContent->GetParent()->AsElement()->AsXULSelectControl();
     if (!select) {
       return nullptr;
     }