Add a new top-level inspector timeline event for the PrePaint step

third_party/WebKit/Source/core/inspector/InspectorTraceEvents.cpp

Index: third_party/WebKit/Source/core/inspector/InspectorTraceEvents.cpp
diff --git a/third_party/WebKit/Source/core/inspector/InspectorTraceEvents.cpp b/third_party/WebKit/Source/core/inspector/InspectorTraceEvents.cpp
index 8280c6a3594906154b5548b4b56c696fc44cbd72..bb9fc2646fabd8239c080770e17c035f962dbd09 100644
--- a/third_party/WebKit/Source/core/inspector/InspectorTraceEvents.cpp
+++ b/third_party/WebKit/Source/core/inspector/InspectorTraceEvents.cpp
@@ -774,6 +774,13 @@ std::unique_ptr<TracedValue> InspectorLayerInvalidationTrackingEvent::data(
   return value;
 }
 
+std::unique_ptr<TracedValue> InspectorPreparePaintEvent::data(
+    LocalFrame* frame) {
+  std::unique_ptr<TracedValue> value = TracedValue::create();
+  value->setString("frame", toHexString(frame));
+  return value;
+}
+
 std::unique_ptr<TracedValue> InspectorPaintEvent::data(
     LayoutObject* layoutObject,
     const LayoutRect& clipRect,