Bug 1454233: Ensure some casts and GetParentElement get inlined. r=bz

GetParentElement was using AsElement before being defined. This is only fine
because AsElement wasn't actually getting inlined in this case.

MozReview-Commit-ID: K41hSBEmIU0

dom/base/Element.h

@@ -2035,6 +2035,11 @@ inline const mozilla::dom::Element* nsINode::AsElement() const
   return static_cast<const mozilla::dom::Element*>(this);
 }
 
+inline mozilla::dom::Element* nsINode::GetParentElement() const
+{
+  return mParent && mParent->IsElement() ? mParent->AsElement() : nullptr;
+}
+
 /**
  * Macros to implement Clone(). _elementName is the class for which to implement
  * Clone.

dom/base/nsIContent.h

@@ -940,6 +940,11 @@ inline nsIContent* nsINode::AsContent()
   return static_cast<nsIContent*>(this);
 }
 
+inline const nsIContent* nsINode::AsContent() const
+{
+  return const_cast<nsINode*>(this)->AsContent();
+}
+
 // Some checks are faster to do on nsIContent or Element than on
 // nsINode, so spit out FromNode versions taking those types too.
 #define NS_IMPL_FROMNODE_HELPER(_class, _check)                         \

dom/base/nsINode.h

@@ -498,18 +498,15 @@ public:
    * Return this node as an Element.  Should only be used for nodes
    * for which IsElement() is true.  This is defined inline in Element.h.
    */
-  mozilla::dom::Element* AsElement();
-  const mozilla::dom::Element* AsElement() const;
+  inline mozilla::dom::Element* AsElement();
+  inline const mozilla::dom::Element* AsElement() const;
 
   /**
    * Return this node as nsIContent.  Should only be used for nodes for which
    * IsContent() is true.  This is defined inline in nsIContent.h.
    */
-  nsIContent* AsContent();
-  const nsIContent* AsContent() const
-  {
-    return const_cast<nsINode*>(this)->AsContent();
-  }
+  inline nsIContent* AsContent();
+  inline const nsIContent* AsContent() const;
 
   /*
    * Return whether the node is a Text node (which might be an actual
@@ -525,15 +522,15 @@ public:
    * Return this node as Text if it is one, otherwise null.  This is defined
    * inline in Text.h.
    */
-  mozilla::dom::Text* GetAsText();
-  const mozilla::dom::Text* GetAsText() const;
+  inline mozilla::dom::Text* GetAsText();
+  inline const mozilla::dom::Text* GetAsText() const;
 
   /**
    * Return this node as Text.  Asserts IsText().  This is defined inline in
    * Text.h.
    */
-  mozilla::dom::Text* AsText();
-  const mozilla::dom::Text* AsText() const;
+  inline mozilla::dom::Text* AsText();
+  inline const mozilla::dom::Text* AsText() const;
 
   /*
    * Return whether the node is a ProcessingInstruction node.
@@ -1011,12 +1008,12 @@ public:
 
   /**
    * Get the parent nsINode for this node if it is an Element.
+   *
+   * Defined inline in Element.h
+   *
    * @return the parent node
    */
-  mozilla::dom::Element* GetParentElement() const
-  {
-    return mParent && mParent->IsElement() ? mParent->AsElement() : nullptr;
-  }
+  inline mozilla::dom::Element* GetParentElement() const;
 
   /**
    * Get the parent Element of this node, traversing over a ShadowRoot