Print creator's call-stack on URLRequestContextGetter leak in Debug.

net/url_request/url_request_context_getter.cc

Index: net/url_request/url_request_context_getter.cc
diff --git a/net/url_request/url_request_context_getter.cc b/net/url_request/url_request_context_getter.cc
index 0bad74812804739ecd53fae8180316ed33213818..7163f48fd265ff79e286cbce224a5a4271c21d61 100644
--- a/net/url_request/url_request_context_getter.cc
+++ b/net/url_request/url_request_context_getter.cc
@@ -40,8 +40,10 @@ void URLRequestContextGetter::OnDestruct() const {
         // Can't force-delete the object here, because some derived classes
         // can only be deleted on the owning thread, so just emit a warning to
         // aid in debugging.
+#if !defined(NDEBUG)

[Ryan Sleevi, 2017/02/22 19:45:57]

Did you mean to remove this logging for !NDEBUG builds?

[Wez, 2017/02/22 22:18:42]

This is already a DLOG(), so compiles to a void stream in NDEBUG builds. I
think.

/me runs off to check.

Yup, that is at least what DLOG is documented as doing.

         DLOG(WARNING) << "URLRequestContextGetter leaking due to no owning"
-                      << " thread.";
+                      << " thread. Created at: " << created_at.ToString();
+#endif  // !defined(NDEBUG)
         // Let LSan know we know this is a leak. https://crbug.com/594130
         ANNOTATE_LEAKING_OBJECT_PTR(this);
       }