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