Bug 1773070 - Unify Gecko and Servo EventState/ElementState bits. r=smaug

Add a dom/base/rust crate called just "dom" where we can share these.

Most of the changes are automatic:

  s/mozilla::EventStates/mozilla::dom::ElementState/
  s/EventStates/ElementState/
  s/NS_EVENT_STATE_/ElementState::/
  s/NS_DOCUMENT_STATE_/DocumentState::/

And so on. This requires a new cbindgen version to avoid ugly casts for
large shifts.

Differential Revision: https://phabricator.services.mozilla.com/D148537

layout/base/nsCSSFrameConstructor.cpp

@@ -23,7 +23,6 @@
 #include "mozilla/dom/HTMLSelectElement.h"
 #include "mozilla/dom/HTMLSharedListElement.h"
 #include "mozilla/dom/HTMLSummaryElement.h"
-#include "mozilla/EventStates.h"
 #include "mozilla/Likely.h"
 #include "mozilla/LinkedList.h"
 #include "mozilla/MemoryReporting.h"
@@ -3615,7 +3614,7 @@ nsCSSFrameConstructor::FindObjectData(const Element& aElement,
   // cases when the object is broken/suppressed/etc (e.g. a broken image), but
   // we want to treat those cases as TYPE_NULL
   uint32_t type;
-  if (aElement.State().HasState(NS_EVENT_STATE_BROKEN)) {
+  if (aElement.State().HasState(ElementState::BROKEN)) {
     type = nsIObjectLoadingContent::TYPE_NULL;
   } else {
     nsCOMPtr<nsIObjectLoadingContent> objContent =