Add scoped_ptr<>::PassAs<>().

base/memory/scoped_ptr_unittest.cc

 // 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.
 
 #include "base/basictypes.h"
 #include "base/memory/scoped_ptr.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace {
 
@@ skipping 27 matching lines @@
 
 void GrabAndDrop(scoped_ptr<ConDecLogger> logger) {
 }
 
 // Do not delete this function!  It's existence is to test that you can
 // return a temporarily constructed version of the scoper.
 scoped_ptr<ConDecLogger> TestReturnOfType(int* constructed) {
   return scoped_ptr<ConDecLogger>(new ConDecLogger(constructed));
 }
 
+scoped_ptr<ConDecLoggerParent> UpcastUsingPassAs(
+    scoped_ptr<ConDecLogger> object) {
+  return object.PassAs<ConDecLoggerParent>();
+}
+
 }  // namespace
 
 TEST(ScopedPtrTest, ScopedPtr) {
   int constructed = 0;
 
   {
     scoped_ptr<ConDecLogger> scoper(new ConDecLogger(&constructed));
     EXPECT_EQ(1, constructed);
     EXPECT_TRUE(scoper.get());
 
@@ skipping 268 matching lines @@
   EXPECT_EQ(0, constructed);
 
   // Call TestReturnOfType() so the compiler doesn't warn for an unused
   // function.
   {
     TestReturnOfType(&constructed);
   }
   EXPECT_EQ(0, constructed);
 }
 
+TEST(ScopedPtrTest, PassAs) {
+  int constructed = 0;
+  {
+    scoped_ptr<ConDecLogger> scoper(new ConDecLogger(&constructed));
+    EXPECT_EQ(1, constructed);
+    EXPECT_TRUE(scoper.get());
+
+    scoped_ptr<ConDecLoggerParent> scoper_parent;
+    scoper_parent = UpcastUsingPassAs(scoper.Pass());
+    EXPECT_EQ(1, constructed);
+    EXPECT_TRUE(scoper_parent.get());
+    EXPECT_FALSE(scoper.get());
+  }
+  EXPECT_EQ(0, constructed);
+}
+
 // TODO scoped_ptr_malloc