Update from https://crrev.com/312398

base/mac/scoped_nsobject.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef BASE_MAC_SCOPED_NSOBJECT_H_
 #define BASE_MAC_SCOPED_NSOBJECT_H_
 
 #import <Foundation/Foundation.h>
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
@@ skipping 22 matching lines @@
 
 template<typename NST>
 class scoped_nsprotocol {
  public:
   explicit scoped_nsprotocol(NST object = nil) : object_(object) {}
 
   scoped_nsprotocol(const scoped_nsprotocol<NST>& that)
       : object_([that.object_ retain]) {
   }
 
+  template <typename NSU>
+  scoped_nsprotocol(const scoped_nsprotocol<NSU>& that)
+      : object_([that.get() retain]) {
+  }
+
   ~scoped_nsprotocol() {
     [object_ release];
   }
 
   scoped_nsprotocol& operator=(const scoped_nsprotocol<NST>& that) {
     reset([that.get() retain]);
     return *this;
   }
 
   void reset(NST object = nil) {
@@ skipping 59 matching lines @@
 template<typename NST>
 class scoped_nsobject : public scoped_nsprotocol<NST*> {
  public:
   explicit scoped_nsobject(NST* object = nil)
       : scoped_nsprotocol<NST*>(object) {}
 
   scoped_nsobject(const scoped_nsobject<NST>& that)
       : scoped_nsprotocol<NST*>(that) {
   }
 
+  template<typename NSU>
+  scoped_nsobject(const scoped_nsobject<NSU>& that)
+      : scoped_nsprotocol<NST*>(that) {
+  }
+
   scoped_nsobject& operator=(const scoped_nsobject<NST>& that) {
     scoped_nsprotocol<NST*>::operator=(that);
     return *this;
   }
 };
 
 // Specialization to make scoped_nsobject<id> work.
 template<>
 class scoped_nsobject<id> : public scoped_nsprotocol<id> {
  public:
   explicit scoped_nsobject(id object = nil) : scoped_nsprotocol<id>(object) {}
 
   scoped_nsobject(const scoped_nsobject<id>& that)
       : scoped_nsprotocol<id>(that) {
   }
 
+  template<typename NSU>
+  scoped_nsobject(const scoped_nsobject<NSU>& that)
+      : scoped_nsprotocol<id>(that) {
+  }
+
   scoped_nsobject& operator=(const scoped_nsobject<id>& that) {
     scoped_nsprotocol<id>::operator=(that);
     return *this;
   }
 };
 
 // Do not use scoped_nsobject for NSAutoreleasePools, use
 // ScopedNSAutoreleasePool instead. This is a compile time check. See details
 // at top of header.
 template<>
 class scoped_nsobject<NSAutoreleasePool> {
  private:
   explicit scoped_nsobject(NSAutoreleasePool* object = nil);
   DISALLOW_COPY_AND_ASSIGN(scoped_nsobject);
 };
 
 }  // namespace base
 
 #endif  // BASE_MAC_SCOPED_NSOBJECT_H_