Bug 1652942 - Remove some unnecessary includes of Element.h. r=smaug

Depends on D83632

Differential Revision: https://phabricator.services.mozilla.com/D83633

dom/base/AnonymousContent.cpp

@@ -8,6 +8,7 @@
 #include "mozilla/PresShell.h"
 #include "mozilla/dom/Document.h"
 #include "mozilla/dom/Element.h"
+#include "mozilla/dom/Event.h"
 #include "mozilla/dom/AnonymousContentBinding.h"
 #include "nsComputedDOMStyle.h"
 #include "nsCycleCollectionParticipant.h"

dom/base/AnonymousContent.h

@@ -7,17 +7,24 @@
 #ifndef mozilla_dom_AnonymousContent_h
 #define mozilla_dom_AnonymousContent_h
 
-#include "mozilla/dom/Element.h"
-#include "mozilla/dom/Event.h"
 #include "nsCycleCollectionParticipant.h"
-#include "nsICSSDeclaration.h"
-#include "mozilla/dom/Document.h"
+
+class nsIPrincipal;
 
 namespace mozilla {
+class ErrorResult;
+
 namespace dom {
 
+class Animation;
+class DOMRect;
+class DOMString;
 class Element;
+class Event;
+template <typename T>
+class Sequence;
 class UnrestrictedDoubleOrAnonymousKeyframeAnimationOptions;
+class UnrestrictedDoubleOrKeyframeAnimationOptions;
 
 class AnonymousContent final {
  public:

dom/flex/Flex.h

@@ -7,7 +7,6 @@
 #ifndef mozilla_dom_Flex_h
 #define mozilla_dom_Flex_h
 
-#include "mozilla/dom/Element.h"
 #include "mozilla/dom/FlexBinding.h"
 #include "nsISupports.h"
 #include "nsWrapperCache.h"
@@ -17,6 +16,7 @@ class nsFlexContainerFrame;
 namespace mozilla {
 namespace dom {
 
+class Element;
 class FlexLineValues;
 
 class Flex : public nsISupports, public nsWrapperCache {

dom/mathml/MathMLElement.h

@@ -8,10 +8,8 @@
 #define mozilla_dom_MathMLElement_h_
 
 #include "mozilla/Attributes.h"
-#include "mozilla/dom/Element.h"
 #include "nsMappedAttributeElement.h"
 #include "Link.h"
-#include "mozilla/dom/DOMRect.h"
 
 class nsCSSValue;