DanglingPtr: mark leaked raw_ptr with LeakedDanglingUntriaged [1/N]

Those leaked raw_ptr were found in a previous CL (crrev.com/c/4501235/)
but the new tag was just introduced.

Bug: 1425095
Change-Id: Iac17934dca6714c202202794e3502f1b0d2aa79c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4580217
Owners-Override: Arthur Sonzogni <[email protected]>
Commit-Queue: Paul Semel <[email protected]>
Reviewed-by: Arthur Sonzogni <[email protected]>
Cr-Commit-Position: refs/heads/main@{#1153926}
diff --git a/base/scoped_observation.h b/base/scoped_observation.h
index 77403392..3cd6882 100644
--- a/base/scoped_observation.h
+++ b/base/scoped_observation.h
@@ -132,7 +132,7 @@
   const raw_ptr<Observer, DanglingUntriaged> observer_;
 
   // The observed source, if any.
-  raw_ptr<Source, DanglingUntriaged> source_ = nullptr;
+  raw_ptr<Source, LeakedDanglingUntriaged> source_ = nullptr;
 };
 
 }  // namespace base