Bug 1456588 part 4. Change nsFocusManager guts to make it clearer that the focused thing is always an Element. r=enndeakin

I couldn't find a good way to make this incremental without adding QIs and
AsElement() in various places....

dom/base/nsFocusManager.cpp

@@ -302,7 +302,7 @@ GetCurrentWindow(nsIContent* aContent)
 }
 
 // static
-nsIContent*
+Element*
 nsFocusManager::GetFocusedDescendant(nsPIDOMWindowOuter* aWindow,
                                      SearchRange aSearchRange,
                                      nsPIDOMWindowOuter** aFocusedWindow)
@@ -311,7 +311,7 @@ nsFocusManager::GetFocusedDescendant(nsPIDOMWindowOuter* aWindow,
 
   *aFocusedWindow = nullptr;
 
-  nsIContent* currentContent = nullptr;
+  Element* currentContent = nullptr;
   nsPIDOMWindowOuter* window = aWindow;
   for (;;) {
     *aFocusedWindow = window;
@@ -349,7 +349,7 @@ nsFocusManager::GetFocusedDescendant(nsPIDOMWindowOuter* aWindow,
 }
 
 // static
-nsIContent*
+Element*
 nsFocusManager::GetRedirectedFocus(nsIContent* aContent)
 {
   // For input number, redirect focus to our anonymous text control.
@@ -365,7 +365,7 @@ nsFocusManager::GetRedirectedFocus(nsIContent* aContent)
       if (numberControlFrame) {
         HTMLInputElement* textControl =
           numberControlFrame->GetAnonTextControl();
-        return static_cast<nsIContent*>(textControl);
+        return textControl;
       }
     }
   }
@@ -392,13 +392,13 @@ nsFocusManager::GetRedirectedFocus(nsIContent* aContent)
         if (children) {
           nsIContent* child = children->Item(0);
           if (child && child->IsXULElement(nsGkAtoms::slider))
-            return child;
+            return child->AsElement();
         }
       }
     }
 
     if (inputField) {
-      nsCOMPtr<nsIContent> retval = do_QueryInterface(inputField);
+      nsCOMPtr<Element> retval = do_QueryInterface(inputField);
       return retval;
     }
   }
@@ -527,14 +527,12 @@ nsFocusManager::SetFocus(Element* aElement, uint32_t aFlags)
 }
 
 NS_IMETHODIMP
-nsFocusManager::ElementIsFocusable(nsIDOMElement* aElement, uint32_t aFlags,
+nsFocusManager::ElementIsFocusable(Element* aElement, uint32_t aFlags,
                                    bool* aIsFocusable)
 {
   NS_ENSURE_TRUE(aElement, NS_ERROR_INVALID_ARG);
 
-  nsCOMPtr<nsIContent> aContent = do_QueryInterface(aElement);
-
-  *aIsFocusable = CheckIfFocusable(aContent, aFlags) != nullptr;
+  *aIsFocusable = CheckIfFocusable(aElement, aFlags) != nullptr;
 
   return NS_OK;
 }
@@ -762,7 +760,7 @@ nsFocusManager::WindowRaised(mozIDOMWindowProxy* aWindow)
 
   // retrieve the last focused element within the window that was raised
   nsCOMPtr<nsPIDOMWindowOuter> currentWindow;
-  nsCOMPtr<nsIContent> currentFocus =
+  RefPtr<Element> currentFocus =
     GetFocusedDescendant(window, eIncludeAllDescendants,
                          getter_AddRefs(currentWindow));
 
@@ -936,7 +934,7 @@ nsFocusManager::WindowShown(mozIDOMWindowProxy* aWindow, bool aNeedsFocus)
 
   if (aNeedsFocus) {
     nsCOMPtr<nsPIDOMWindowOuter> currentWindow;
-    nsCOMPtr<nsIContent> currentFocus =
+    RefPtr<Element> currentFocus =
       GetFocusedDescendant(window, eIncludeAllDescendants,
                            getter_AddRefs(currentWindow));
     if (currentWindow)
@@ -1229,7 +1227,7 @@ nsFocusManager::SetFocusInner(Element* aNewContent, int32_t aFlags,
                               bool aFocusChanged, bool aAdjustWidget)
 {
   // if the element is not focusable, just return and leave the focus as is
-  nsCOMPtr<nsIContent> contentToFocus = CheckIfFocusable(aNewContent, aFlags);
+  RefPtr<Element> contentToFocus = CheckIfFocusable(aNewContent, aFlags);
   if (!contentToFocus)
     return;
 
@@ -1580,17 +1578,18 @@ nsFocusManager::IsNonFocusableRoot(nsIContent* aContent)
             nsContentUtils::IsUserFocusIgnored(aContent));
 }
 
-nsIContent*
-nsFocusManager::CheckIfFocusable(nsIContent* aContent, uint32_t aFlags)
+Element*
+nsFocusManager::CheckIfFocusable(Element* aContent, uint32_t aFlags)
 {
   if (!aContent)
     return nullptr;
 
   // this is a special case for some XUL elements or input number, where an
   // anonymous child is actually focusable and not the element itself.
-  nsCOMPtr<nsIContent> redirectedFocus = GetRedirectedFocus(aContent);
-  if (redirectedFocus)
+  RefPtr<Element> redirectedFocus = GetRedirectedFocus(aContent);
+  if (redirectedFocus) {
     return CheckIfFocusable(redirectedFocus, aFlags);
+  }
 
   nsCOMPtr<nsIDocument> doc = aContent->GetComposedDoc();
   // can't focus elements that are not in documents
@@ -1610,8 +1609,9 @@ nsFocusManager::CheckIfFocusable(nsIContent* aContent, uint32_t aFlags)
 
   // the root content can always be focused,
   // except in userfocusignored context.
-  if (aContent == doc->GetRootElement())
+  if (aContent == doc->GetRootElement()) {
     return nsContentUtils::IsUserFocusIgnored(aContent) ? nullptr : aContent;
+  }
 
   // cannot focus content in print preview mode. Only the root can be focused.
   nsPresContext* presContext = shell->GetPresContext();
@@ -1834,7 +1834,7 @@ nsFocusManager::Blur(nsPIDOMWindowOuter* aWindowToClear,
 
 void
 nsFocusManager::Focus(nsPIDOMWindowOuter* aWindow,
-                      nsIContent* aContent,
+                      Element* aContent,
                       uint32_t aFlags,
                       bool aIsNewDocument,
                       bool aFocusChanged,

dom/base/nsFocusManager.h

@@ -143,9 +143,10 @@ public:
     // Return focused content in aWindow or one of visible sub windows.
     eIncludeVisibleDescendants,
   };
-  static nsIContent* GetFocusedDescendant(nsPIDOMWindowOuter* aWindow,
-                                          SearchRange aSearchRange,
-                                          nsPIDOMWindowOuter** aFocusedWindow);
+  static mozilla::dom::Element*
+  GetFocusedDescendant(nsPIDOMWindowOuter* aWindow,
+                       SearchRange aSearchRange,
+                       nsPIDOMWindowOuter** aFocusedWindow);
 
   /**
    * Returns the content node that focus will be redirected to if aContent was
@@ -157,7 +158,7 @@ public:
    * XXXndeakin this should be removed eventually but I want to do that as
    * followup work.
    */
-  static nsIContent* GetRedirectedFocus(nsIContent* aContent);
+  static mozilla::dom::Element* GetRedirectedFocus(nsIContent* aContent);
 
   /**
    * Returns an InputContextAction cause for aFlags.
@@ -245,7 +246,8 @@ protected:
    * frame, so only the IsFocusable method on the content node must be
    * true.
    */
-  nsIContent* CheckIfFocusable(nsIContent* aContent, uint32_t aFlags);
+  mozilla::dom::Element* CheckIfFocusable(mozilla::dom::Element* aContent,
+                                          uint32_t aFlags);
 
   /**
    * Blurs the currently focused element. Returns false if another element was
@@ -303,7 +305,7 @@ protected:
    * If aAdjustWidget is false, don't change the widget focus state.
    */
   void Focus(nsPIDOMWindowOuter* aWindow,
-             nsIContent* aContent,
+             mozilla::dom::Element* aContent,
              uint32_t aFlags,
              bool aIsNewDocument,
              bool aFocusChanged,

dom/base/nsGlobalWindowInner.cpp

@@ -4652,7 +4652,7 @@ static bool ShouldShowFocusRingIfFocusedByMouse(nsIContent* aNode)
 }
 
 void
-nsGlobalWindowInner::SetFocusedNode(nsIContent* aNode,
+nsGlobalWindowInner::SetFocusedNode(Element* aNode,
                                     uint32_t aFocusMethod,
                                     bool aNeedsFocus)
 {

dom/base/nsGlobalWindowInner.h

@@ -1197,7 +1197,7 @@ public:
 
   bool IsInModalState();
 
-  virtual void SetFocusedNode(nsIContent* aNode,
+  virtual void SetFocusedNode(mozilla::dom::Element* aNode,
                               uint32_t aFocusMethod = 0,
                               bool aNeedsFocus = false) override;
 

dom/base/nsGlobalWindowOuter.cpp

@@ -6624,7 +6624,7 @@ nsGlobalWindowOuter::SetChromeEventHandler(EventTarget* aChromeEventHandler)
 }
 
 void
-nsGlobalWindowOuter::SetFocusedNode(nsIContent* aNode,
+nsGlobalWindowOuter::SetFocusedNode(Element* aNode,
                                     uint32_t aFocusMethod,
                                     bool aNeedsFocus)
 {
@@ -6676,13 +6676,12 @@ nsGlobalWindowOuter::SetKeyboardIndicators(UIStateChangeType aShowAccelerators,
   bool newShouldShowFocusRing = ShouldShowFocusRing();
   if (mInnerWindow && nsGlobalWindowInner::Cast(mInnerWindow)->mHasFocus &&
       mInnerWindow->mFocusedNode &&
-      oldShouldShowFocusRing != newShouldShowFocusRing &&
-      mInnerWindow->mFocusedNode->IsElement()) {
+      oldShouldShowFocusRing != newShouldShowFocusRing) {
     // Update focusedNode's state.
     if (newShouldShowFocusRing) {
-      mInnerWindow->mFocusedNode->AsElement()->AddStates(NS_EVENT_STATE_FOCUSRING);
+      mInnerWindow->mFocusedNode->AddStates(NS_EVENT_STATE_FOCUSRING);
     } else {
-      mInnerWindow->mFocusedNode->AsElement()->RemoveStates(NS_EVENT_STATE_FOCUSRING);
+      mInnerWindow->mFocusedNode->RemoveStates(NS_EVENT_STATE_FOCUSRING);
     }
   }
 }
@@ -7257,13 +7256,12 @@ nsGlobalWindowOuter::RestoreWindowState(nsISupports *aState)
 
   // if a link is focused, refocus with the FLAG_SHOWRING flag set. This makes
   // it easy to tell which link was last clicked when going back a page.
-  nsIContent* focusedNode = inner->GetFocusedNode();
+  Element* focusedNode = inner->GetFocusedNode();
   if (nsContentUtils::ContentIsLink(focusedNode)) {
     nsIFocusManager* fm = nsFocusManager::GetFocusManager();
     if (fm) {
-      // This AsElement() will go away in a few changesets once we
-      // convert nsPIDOMWindowInner::mFocusedNode to Element.
-      RefPtr<Element> focusedElement = focusedNode->AsElement();
+      // XXXbz Do we need the stack strong ref here?
+      RefPtr<Element> focusedElement = focusedNode;
       fm->SetFocus(focusedElement, nsIFocusManager::FLAG_NOSCROLL |
                                    nsIFocusManager::FLAG_SHOWRING);
     }

dom/base/nsGlobalWindowOuter.h

@@ -979,7 +979,7 @@ public:
   nsIntSize DevToCSSIntPixels(nsIntSize px);
   nsIntSize CSSToDevIntPixels(nsIntSize px);
 
-  virtual void SetFocusedNode(nsIContent* aNode,
+  virtual void SetFocusedNode(mozilla::dom::Element* aNode,
                               uint32_t aFocusMethod = 0,
                               bool aNeedsFocus = false) override;
 

dom/base/nsPIDOMWindow.h

@@ -484,8 +484,8 @@ public:
    * DO NOT CALL EITHER OF THESE METHODS DIRECTLY. USE THE FOCUS MANAGER
    * INSTEAD.
    */
-  inline nsIContent* GetFocusedNode() const;
-  virtual void SetFocusedNode(nsIContent* aNode,
+  inline mozilla::dom::Element* GetFocusedNode() const;
+  virtual void SetFocusedNode(mozilla::dom::Element* aNode,
                               uint32_t aFocusMethod = 0,
                               bool aNeedsFocus = false) = 0;
 
@@ -659,8 +659,8 @@ protected:
   nsCOMPtr<nsPIDOMWindowOuter> mOuterWindow;
 
   // the element within the document that is currently focused when this
-  // window is active
-  nsCOMPtr<nsIContent> mFocusedNode;
+  // window is active.
+  RefPtr<mozilla::dom::Element> mFocusedNode;
 
   // The AudioContexts created for the current document, if any.
   nsTArray<mozilla::dom::AudioContext*> mAudioContexts; // Weak
@@ -973,8 +973,8 @@ public:
    * DO NOT CALL EITHER OF THESE METHODS DIRECTLY. USE THE FOCUS MANAGER
    * INSTEAD.
    */
-  inline nsIContent* GetFocusedNode() const;
-  virtual void SetFocusedNode(nsIContent* aNode,
+  inline mozilla::dom::Element* GetFocusedNode() const;
+  virtual void SetFocusedNode(mozilla::dom::Element* aNode,
                               uint32_t aFocusMethod = 0,
                               bool aNeedsFocus = false) = 0;
 

dom/base/nsPIDOMWindowInlines.h

@@ -89,13 +89,13 @@ nsPIDOMWindowInner::GetDocShell() const
   return mOuterWindow ? mOuterWindow->GetDocShell() : nullptr;
 }
 
-nsIContent*
+mozilla::dom::Element*
 nsPIDOMWindowOuter::GetFocusedNode() const
 {
   return mInnerWindow ? mInnerWindow->GetFocusedNode() : nullptr;
 }
 
-nsIContent*
+mozilla::dom::Element*
 nsPIDOMWindowInner::GetFocusedNode() const
 {
   return mFocusedNode;

dom/interfaces/base/nsIFocusManager.idl

@@ -143,7 +143,7 @@ interface nsIFocusManager : nsISupports
   /***
    * Check if given element is focusable.
    */
-  boolean elementIsFocusable(in nsIDOMElement aElement, in unsigned long aFlags);
+  boolean elementIsFocusable(in Element aElement, in unsigned long aFlags);
 
   /*
    * Raise the window when switching focus