Bug 1694573 part 5: Make LocalAccessible call Platform*Event. Remove most of the platform HandleAccEvent overrides. r=eeejay

Mac and Android still override HandleAccEvent for platform specific behaviour other than firing the event.
The Android behaviour can be unified properly in future work.

ATK is the platform layer with the most churn because there were inconsistencies in the way local and remote events were handled.
I'm reasonably sure these were unintentional inconsistencies, so I've done my best to unify them.

Differential Revision: https://phabricator.services.mozilla.com/D183704

accessible/generic/LocalAccessible.cpp

@@ -13,6 +13,7 @@
 #include "DocAccessible-inl.h"
 #include "mozilla/a11y/AccAttributes.h"
 #include "mozilla/a11y/DocAccessibleChild.h"
+#include "mozilla/a11y/Platform.h"
 #include "nsAccUtils.h"
 #include "nsAccessibilityService.h"
 #include "ApplicationAccessible.h"
@@ -994,6 +995,115 @@ nsresult LocalAccessible::HandleAccEvent(AccEvent* aEvent) {
     nsCoreUtils::DispatchAccEvent(MakeXPCEvent(aEvent));
   }
 
+  if (IPCAccessibilityActive()) {
+    return NS_OK;
+  }
+
+  if (IsDefunct()) {
+    // This could happen if there is an XPCOM observer, since script might run
+    // which mutates the tree.
+    return NS_OK;
+  }
+
+  LocalAccessible* target = aEvent->GetAccessible();
+  switch (aEvent->GetEventType()) {
+    case nsIAccessibleEvent::EVENT_SHOW:
+      PlatformShowHideEvent(target, target->LocalParent(), true,
+                            aEvent->IsFromUserInput());
+      break;
+    case nsIAccessibleEvent::EVENT_HIDE:
+      PlatformShowHideEvent(target, target->LocalParent(), false,
+                            aEvent->IsFromUserInput());
+      break;
+    case nsIAccessibleEvent::EVENT_STATE_CHANGE: {
+      AccStateChangeEvent* event = downcast_accEvent(aEvent);
+      PlatformStateChangeEvent(target, event->GetState(),
+                               event->IsStateEnabled());
+      break;
+    }
+    case nsIAccessibleEvent::EVENT_TEXT_CARET_MOVED: {
+      AccCaretMoveEvent* event = downcast_accEvent(aEvent);
+      LayoutDeviceIntRect rect;
+      // The caret rect is only used on Windows, so just pass an empty rect on
+      // other platforms.
+      // XXX We pass an empty rect on Windows as well because
+      // AccessibleWrap::UpdateSystemCaretFor currently needs to call
+      // HyperTextAccessible::GetCaretRect again to get the widget and there's
+      // no point calling it twice.
+      PlatformCaretMoveEvent(target, event->GetCaretOffset(),
+                             event->IsSelectionCollapsed(),
+                             event->GetGranularity(), rect);
+      break;
+    }
+    case nsIAccessibleEvent::EVENT_TEXT_INSERTED:
+    case nsIAccessibleEvent::EVENT_TEXT_REMOVED: {
+      AccTextChangeEvent* event = downcast_accEvent(aEvent);
+      const nsString& text = event->ModifiedText();
+      PlatformTextChangeEvent(target, text, event->GetStartOffset(),
+                              event->GetLength(), event->IsTextInserted(),
+                              event->IsFromUserInput());
+      break;
+    }
+    case nsIAccessibleEvent::EVENT_SELECTION:
+    case nsIAccessibleEvent::EVENT_SELECTION_ADD:
+    case nsIAccessibleEvent::EVENT_SELECTION_REMOVE: {
+      AccSelChangeEvent* selEvent = downcast_accEvent(aEvent);
+      PlatformSelectionEvent(target, selEvent->Widget(),
+                             aEvent->GetEventType());
+      break;
+    }
+    case nsIAccessibleEvent::EVENT_VIRTUALCURSOR_CHANGED: {
+#ifdef ANDROID
+      AccVCChangeEvent* vcEvent = downcast_accEvent(aEvent);
+      PlatformVirtualCursorChangeEvent(
+          target, vcEvent->OldAccessible(), vcEvent->NewAccessible(),
+          vcEvent->Reason(), vcEvent->IsFromUserInput());
+#endif
+      break;
+    }
+    case nsIAccessibleEvent::EVENT_FOCUS: {
+      LayoutDeviceIntRect rect;
+      // The caret rect is only used on Windows, so just pass an empty rect on
+      // other platforms.
+#ifdef XP_WIN
+      if (HyperTextAccessible* text = target->AsHyperText()) {
+        nsIWidget* widget = nullptr;
+        rect = text->GetCaretRect(&widget);
+      }
+#endif
+      PlatformFocusEvent(target, rect);
+      break;
+    }
+#if defined(ANDROID)
+    case nsIAccessibleEvent::EVENT_SCROLLING_END:
+    case nsIAccessibleEvent::EVENT_SCROLLING: {
+      AccScrollingEvent* scrollingEvent = downcast_accEvent(aEvent);
+      PlatformScrollingEvent(
+          target, aEvent->GetEventType(), scrollingEvent->ScrollX(),
+          scrollingEvent->ScrollY(), scrollingEvent->MaxScrollX(),
+          scrollingEvent->MaxScrollY());
+      break;
+    }
+    case nsIAccessibleEvent::EVENT_ANNOUNCEMENT: {
+      AccAnnouncementEvent* announcementEvent = downcast_accEvent(aEvent);
+      PlatformAnnouncementEvent(target, announcementEvent->Announcement(),
+                                announcementEvent->Priority());
+      break;
+    }
+#endif  // defined(ANDROID)
+#if defined(MOZ_WIDGET_COCOA)
+    case nsIAccessibleEvent::EVENT_TEXT_SELECTION_CHANGED: {
+      AccTextSelChangeEvent* textSelChangeEvent = downcast_accEvent(aEvent);
+      AutoTArray<TextRange, 1> ranges;
+      textSelChangeEvent->SelectionRanges(&ranges);
+      PlatformTextSelectionChangeEvent(target, ranges);
+      break;
+    }
+#endif  // defined(MOZ_WIDGET_COCOA)
+    default:
+      PlatformEvent(target, aEvent->GetEventType());
+  }
+
   return NS_OK;
 }