Complete live region support in ChromeVox Next.

chrome/common/extensions/api/automation.idl

Index: chrome/common/extensions/api/automation.idl
diff --git a/chrome/common/extensions/api/automation.idl b/chrome/common/extensions/api/automation.idl
index c6f02b9b9c3cce59b177f9cee2841106b663c388..56c728fdf705d0073ff724089a9122372fa61b42 100644
--- a/chrome/common/extensions/api/automation.idl
+++ b/chrome/common/extensions/api/automation.idl
@@ -317,6 +317,14 @@
     TreeChangeType type;
   };
 
+  // Possible tree changes to listen to using addTreeChangeObserver.
+  // Note that listening to all tree changes can be expensive.
+  enum TreeChangeObserverFilter {
+    noTreeChanges,
+    liveRegionTreeChanges,
+    allTreeChanges
+  };
+
   // A listener for changes on the <code>AutomationNode</code> tree.
   callback TreeChangeObserver = void(TreeChange treeChange);
 
@@ -579,9 +587,11 @@
     [nocompile] static void getDesktop(RootCallback callback);
 
     // Add a tree change observer. Tree change observers are static/global, they
-    // listen to changes across all trees.
+    // listen to changes across all trees. Pass a filter to determine what
+    // specific tree changes to listen to, and note that listnening to all
+    // tree changes can be expensive.
     [nocompile] static void addTreeChangeObserver(
-        TreeChangeObserver observer);
+        TreeChangeObserverFilter filter, TreeChangeObserver observer);
 
     // Remove a tree change observer.
     [nocompile] static void removeTreeChangeObserver(