Mandate unique_ptr for base::IDMap in IDMapOwnPointer mode.

base/id_map.h

Index: base/id_map.h
diff --git a/base/id_map.h b/base/id_map.h
index 8702982f172ffd0f06725207f296104946965d4d..7bdfd429d6dd6841ed859acbd5f13321220dae57 100644
--- a/base/id_map.h
+++ b/base/id_map.h
@@ -17,8 +17,13 @@
 #include "base/macros.h"
 #include "base/sequence_checker.h"
 
-// Ownership semantics - own pointer means the pointer is deleted in Remove()
-// & during destruction
+// Ownership semantics:
+// - OwnPointer means we store a unique_ptr that owns the object (so the
+//   object is deleted in Remove() and during destruction).
+// - ExternalPointer means we store a raw pointer and don't own the object
+
+// TODO (http://crbug.com/647091): eliminate this enum, replace OwnPointer
+// mode in callsites with IDMap<unique_ptr<T>>
 enum IDMapOwnershipSemantics {
   IDMapExternalPointer,
   IDMapOwnPointer
@@ -82,15 +87,12 @@ class IDMap {
     AddWithIDInternal(std::move(data), id);
   }
 
-  // http://crbug.com/647091: Raw pointer Add()s in IDMapOwnPointer mode are
-  // deprecated.  Users of IDMapOwnPointer should transition to the unique_ptr
-  // variant above, and the following methods should only be used in
-  // IDMapExternalPointer mode.
+  // The following two methods are used in IDMapExternalPointer mode.
   KeyType Add(T* data) {

[aelias_OOO_until_Jul13, 2016/11/08 01:55:09]

I don't think the explicit overloading is needed anymore, you can replace both
Add(std::unique_ptr<T>) and Add(T*) with Add(V).

-    return AddInternal(V(data));
+    return AddInternal(data);
   }
   void AddWithID(T* data, KeyType id) {
-    AddWithIDInternal(V(data), id);
+    AddWithIDInternal(data, id);
   }
 
   void Remove(KeyType id) {