Tie DragState to DragController.

third_party/WebKit/Source/core/page/DragController.cpp

Index: third_party/WebKit/Source/core/page/DragController.cpp
diff --git a/third_party/WebKit/Source/core/page/DragController.cpp b/third_party/WebKit/Source/core/page/DragController.cpp
index b4ff4107dbb5dd67d469fa394220495661fb804c..c762db63118a2e3aa779234d825e5f63202e1c73 100644
--- a/third_party/WebKit/Source/core/page/DragController.cpp
+++ b/third_party/WebKit/Source/core/page/DragController.cpp
@@ -1229,10 +1229,17 @@ bool DragController::isCopyKeyDown(DragData* dragData) {
 #endif
 }
 
+DragState& DragController::dragState() {
+  if (!m_dragState)
+    m_dragState = new DragState;
+  return *m_dragState;
+}
+
 DEFINE_TRACE(DragController) {
   visitor->trace(m_page);
   visitor->trace(m_documentUnderMouse);
   visitor->trace(m_dragInitiator);
+  visitor->trace(m_dragState);
   visitor->trace(m_fileInputElementUnderMouse);
 }