Expose an interface to generate a unique accessibility ID.

third_party/WebKit/public/web/WebAXObject.h

Index: third_party/WebKit/public/web/WebAXObject.h
diff --git a/third_party/WebKit/public/web/WebAXObject.h b/third_party/WebKit/public/web/WebAXObject.h
index 124f6ceffebbd699ebd7583d52a1e35aa35bb10a..49c0a7955ace9c37acf6939d7e7341ec6bee578e 100644
--- a/third_party/WebKit/public/web/WebAXObject.h
+++ b/third_party/WebKit/public/web/WebAXObject.h
@@ -93,6 +93,10 @@ public:
 
     BLINK_EXPORT int axID() const;
 
+    // Get a new AXID that's not used by any accessibility node in this process, for when the
+    // client needs to insert additional nodes into the accessibility tree.
+    BLINK_EXPORT int generateAXID() const;
+
     // Update layout on the underlying tree, and return true if this object is
     // still valid (not detached). Note that calling this method
     // can cause other WebAXObjects to become invalid, too,