Bug 1410482 - enable AOM for privileged content, r=smaug

accessible/aom/AccessibleNode.cpp

@@ -18,7 +18,21 @@ using namespace mozilla;
 using namespace mozilla::a11y;
 using namespace mozilla::dom;
 
-NS_IMPL_CYCLE_COLLECTION_WRAPPERCACHE_0(AccessibleNode)
+bool
+AccessibleNode::IsAOMEnabled(JSContext* aCx, JSObject* /*unused*/)
+{
+  static bool sPrefCached = false;
+  static bool sPrefCacheValue = false;
+
+  if (!sPrefCached) {
+    sPrefCached = true;
+    Preferences::AddBoolVarCache(&sPrefCacheValue, "accessibility.AOM.enabled");
+  }
+
+  return nsContentUtils::IsSystemCaller(aCx) || sPrefCacheValue;
+}
+
+NS_IMPL_CYCLE_COLLECTION_WRAPPERCACHE(AccessibleNode, mIntl, mDOMNode, mStates)
 
 NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(AccessibleNode)
   NS_WRAPPERCACHE_INTERFACE_MAP_ENTRY

accessible/aom/AccessibleNode.h

@@ -47,7 +47,7 @@ public:
            JS::MutableHandle<JS::Value> aValue,
            ErrorResult& aRv);
 
-  a11y::Accessible* Internal() const { return mIntl; }
+  static bool IsAOMEnabled(JSContext*, JSObject*);
 
 protected:
   AccessibleNode(const AccessibleNode& aCopy) = delete;

accessible/base/nsAccessibilityService.cpp

@@ -405,8 +405,9 @@ NS_IMETHODIMP
 nsAccessibilityService::Observe(nsISupports *aSubject, const char *aTopic,
                          const char16_t *aData)
 {
-  if (!nsCRT::strcmp(aTopic, NS_XPCOM_SHUTDOWN_OBSERVER_ID))
+  if (!nsCRT::strcmp(aTopic, NS_XPCOM_SHUTDOWN_OBSERVER_ID)) {
     Shutdown();
+  }
 
   return NS_OK;
 }

dom/webidl/AccessibleNode.webidl

@@ -4,7 +4,7 @@
  * You can obtain one at http://mozilla.org/MPL/2.0/.
  */
 
-[Pref="accessibility.AOM.enabled"]
+[Func="mozilla::dom::AccessibleNode::IsAOMEnabled"]
 interface AccessibleNode {
   readonly attribute DOMString role;
   [Frozen, Cached, Pure]

dom/webidl/Node.webidl

@@ -208,7 +208,7 @@ interface Node : EventTarget {
   Promise<void> localize(L10nCallback l10nCallback);
 
 #ifdef ACCESSIBILITY
-  [Pref="accessibility.AOM.enabled"]
+  [Func="mozilla::dom::AccessibleNode::IsAOMEnabled"]
   readonly attribute AccessibleNode? accessibleNode;
 #endif
 };