Add a |scope| argument to TRACE_EVENT_INSTANT* and require its presence.

content/renderer/render_view_impl.cc

Index: content/renderer/render_view_impl.cc
diff --git a/content/renderer/render_view_impl.cc b/content/renderer/render_view_impl.cc
index 3b1a0d3ed68a1126d77182272b9d272a1fd33d8c..66cbb8c0a2a92ffe70d7455ffa03d79f86d0cec7 100644
--- a/content/renderer/render_view_impl.cc
+++ b/content/renderer/render_view_impl.cc
@@ -3724,6 +3724,8 @@ void RenderViewImpl::didFailLoad(WebFrame* frame, const WebURLError& error) {
 }
 
 void RenderViewImpl::didFinishLoad(WebFrame* frame) {
+  if (!frame->parent())
+    TRACE_EVENT_INSTANT0("WebCore", "LoadEvent", TRACE_EVENT_SCOPE_THREAD);
   WebDataSource* ds = frame->dataSource();
   DocumentState* document_state = DocumentState::FromDataSource(ds);
   if (document_state->finish_load_time().is_null())
@@ -5202,7 +5204,8 @@ void RenderViewImpl::OnScriptEvalRequest(const string16& frame_xpath,
                                          const string16& jscript,
                                          int id,
                                          bool notify_result) {
-  TRACE_EVENT_INSTANT0("test_tracing", "OnScriptEvalRequest");
+  TRACE_EVENT_INSTANT0("test_tracing", "OnScriptEvalRequest",
+                       TRACE_EVENT_SCOPE_THREAD);
   EvaluateScript(frame_xpath, jscript, id, notify_result);
 }