Make WebTraceLocation be an alias of tracked_objects::Location

components/scheduler/child/webthread_base.h

Index: components/scheduler/child/webthread_base.h
diff --git a/components/scheduler/child/webthread_base.h b/components/scheduler/child/webthread_base.h
index 0075d5f39f24742e1582ad47b22a9d224a76c19c..0546cd9e6984b1c6962f201198cf7f3a85c96d78 100644
--- a/components/scheduler/child/webthread_base.h
+++ b/components/scheduler/child/webthread_base.h
@@ -11,10 +11,7 @@
 #include "base/threading/thread.h"
 #include "components/scheduler/scheduler_export.h"
 #include "third_party/WebKit/public/platform/WebThread.h"
-
-namespace blink {
-class WebTraceLocation;
-}
+#include "third_party/WebKit/public/platform/WebTraceLocation.h"
 
 namespace scheduler {
 class SingleThreadIdleTaskRunner;