Navigation transitions (web to native app): Get names and rects of transition elements (Step 2)

Source/core/dom/Document.h

Index: Source/core/dom/Document.h
diff --git a/Source/core/dom/Document.h b/Source/core/dom/Document.h
index 0ab8e673f6c778774b999e2cefa155f4d3780864..2261703631d1f34877af1cada2f0a5ae0dc58f59 100644
--- a/Source/core/dom/Document.h
+++ b/Source/core/dom/Document.h
@@ -386,10 +386,16 @@ public:
     void setIsTransitionDocument() { m_isTransitionDocument = true; }
     void hideTransitionElements(const AtomicString& cssSelector);
 
+    struct TransitionElement {
+        String id;
+        IntRect rect;
+    };
+
     struct TransitionElementData {
         String scope;
         String selector;
         String markup;
+        Vector<TransitionElement> elements;
     };
     void getTransitionElementData(Vector<TransitionElementData>&);