Clean up final uses of scoped_ptr<T>::PassAs() and remove it.

base/memory/scoped_ptr.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.
 
 // Scopers help you manage ownership of a pointer, helping you easily manage a
 // pointer within a scope, and automatically destroying the pointer at the end
 // of a scope.  There are two main classes you will use, which correspond to the
 // operators new/delete and new[]/delete[].
 //
 // Example usage (scoped_ptr<T>):
@@ skipping 55 matching lines @@
 // are not copyable; they only implement move semantics which require calling
 // the Pass() function to signify a destructive transfer of state. CreateFoo()
 // is different though because we are constructing a temporary on the return
 // line and thus can avoid needing to call Pass().
 //
 // Pass() properly handles upcast in initialization, i.e. you can use a
 // scoped_ptr<Child> to initialize a scoped_ptr<Parent>:
 //
 //   scoped_ptr<Foo> foo(new Foo());
 //   scoped_ptr<FooParent> parent(foo.Pass());
-//
-// PassAs<>() should be used to upcast return value in return statement:
-//
-//   scoped_ptr<Foo> CreateFoo() {
-//     scoped_ptr<FooChild> result(new FooChild());
-//     return result.PassAs<Foo>();
-//   }
-//
-// Note that PassAs<>() is implemented only for scoped_ptr<T>, but not for
-// scoped_ptr<T[]>. This is because casting array pointers may not be safe.
 
 #ifndef BASE_MEMORY_SCOPED_PTR_H_
 #define BASE_MEMORY_SCOPED_PTR_H_
 
 // This is an implementation designed to match the anticipated future TR2
 // implementation of the scoped_ptr class.
 
 #include <assert.h>
 #include <stddef.h>
 #include <stdlib.h>
@@ skipping 333 matching lines @@
   }
 
   // Release a pointer.
   // The return value is the current pointer held by this object. If this object
   // holds a nullptr, the return value is nullptr. After this operation, this
   // object will hold a nullptr, and will not own the object any more.
   element_type* release() WARN_UNUSED_RESULT {
     return impl_.release();
   }
 
-  // C++98 doesn't support functions templates with default parameters which
-  // makes it hard to write a PassAs() that understands converting the deleter
-  // while preserving simple calling semantics.
-  //
-  // Until there is a use case for PassAs() with custom deleters, just ignore
-  // the custom deleter.
-  template <typename PassAsType>
-  scoped_ptr<PassAsType> PassAs() {
-    return scoped_ptr<PassAsType>(Pass());
-  }
-
  private:
   // Needed to reach into |impl_| in the constructor.
   template <typename U, typename V> friend class scoped_ptr;
   base::internal::scoped_ptr_impl<element_type, deleter_type> impl_;
 
   // Forbidden for API compatibility with std::unique_ptr.
   explicit scoped_ptr(int disallow_construction_from_null);
 
   // Forbid comparison of scoped_ptr types.  If U != T, it totally
   // doesn't make sense, and if U == T, it still doesn't make sense
@@ skipping 140 matching lines @@
 
 // A function to convert T* into scoped_ptr<T>
 // Doing e.g. make_scoped_ptr(new FooBarBaz<type>(arg)) is a shorter notation
 // for scoped_ptr<FooBarBaz<type> >(new FooBarBaz<type>(arg))
 template <typename T>
 scoped_ptr<T> make_scoped_ptr(T* ptr) {
   return scoped_ptr<T>(ptr);
 }
 
 #endif  // BASE_MEMORY_SCOPED_PTR_H_