Change RefCountedObject to use perfect forwarding.

webrtc/base/refcount_unittest.cc

+/*
+ *  Copyright 2016 The WebRTC Project Authors. All rights reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include <string>
+
+#include "webrtc/base/gunit.h"
+#include "webrtc/base/refcount.h"
+
+namespace rtc {
+
+namespace {
+
+class A {
+ public:
+  A() {}
+
+  RTC_DISALLOW_COPY_AND_ASSIGN(A);

[tommi, 2016/10/18 15:57:58]

private

[perkj_webrtc, 2016/10/19 00:43:14]

Done.

+};
+
+class Aref : public RefCountInterface {
+ public:
+  Aref() {}
+
+ protected:
+  virtual ~Aref() {}
+};
+
+class Bref : public RefCountInterface {
+ public:
+  Bref(std::unique_ptr<A> a) : a_(std::move(a)) {}
+
+ protected:
+  virtual ~Bref() {}
+
+ public:
+  std::unique_ptr<A> a_;
+};
+
+}  // namespace
+
+TEST(RefCountedObject, Basic) {
+  scoped_refptr<RefCountedObject<Aref>> aref(new RefCountedObject<Aref>());

[hbos, 2016/10/18 17:50:04]

Can you add more tests to make sure a constructor works with all parameter
types?
by value
by reference
by rvalue reference
(And make sure that the expected copies happen/don't happen.)

And perhaps a test that has a constructor that takes all three types at the same
time to make sure the implementation works with combinations.

[perkj_webrtc, 2016/10/19 00:43:14]

done. Since we use pump we don't need to test all ctors. Also since we use
universal references I am not sure how much value the last test actually have
but to be complete... 

+  EXPECT_TRUE(aref->HasOneRef());
+  EXPECT_EQ(2, aref->AddRef());
+  EXPECT_EQ(1, aref->Release());
+}
+
+TEST(RefCountedObject, SupportRValuesInCtor) {
+  std::unique_ptr<A> a(new A());
+  scoped_refptr<Bref> bref(new RefCountedObject<Bref>(std::move(a)));
+  EXPECT_TRUE(bref->a_.get() != nullptr);
+  EXPECT_TRUE(a.get() == nullptr);
+}
+
+}  // namespace rtc