cc: Move TextureMailbox::ReleaseCallback to SingleReleaseCallback.

cc/resources/scoped_release_callback.cc

+// Copyright 2013 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 "cc/resources/scoped_release_callback.h"
+
+#include "base/callback_helpers.h"
+#include "base/logging.h"
+
+namespace cc {
+
+ScopedReleaseCallback::ScopedReleaseCallback() {}
+
+ScopedReleaseCallback::ScopedReleaseCallback(const ReleaseCallback& callback)

[awong, 2013/09/13 07:07:19]

Doesn't this already violate the rule that there can only be 1 owner of the
ReleaseCallback?

[danakj, 2013/09/13 17:32:59]

Well, the callback has to come from somewhere. I'd expect a cc/ embedder to call
ScopedReleaseCallback(base::Bind(foo...)). What would you expect?

Also this would allow a ScopedRC to be constructed out of a Leak()

+    : callback_(callback) {}
+
+ScopedReleaseCallback::ScopedReleaseCallback(RValue other)
+    : callback_(base::ResetAndReturn(&other.object->callback_)) {}

[piman, 2013/09/13 06:08:30]

nit: callback_(other.object->Leak())

+
+ScopedReleaseCallback::~ScopedReleaseCallback() {
+  DCHECK(callback_.is_null()) << "ScopedReleaseCallback was never run.";
+}
+
+void ScopedReleaseCallback::RunAndReset(unsigned sync_point, bool is_lost) {
+  base::ResetAndReturn(&callback_).Run(sync_point, is_lost);
+}
+
+ScopedReleaseCallback& ScopedReleaseCallback::operator=(
+    ScopedReleaseCallback rhs) {
+  DCHECK(callback_.is_null());
+  callback_ = rhs.callback_;
+  rhs.callback_ = ReleaseCallback();

[piman, 2013/09/13 06:08:30]

nit: replace those 2 lines by callback_ = rhs.Leak(); ?

+  return *this;
+}
+
+ReleaseCallback ScopedReleaseCallback::Leak() {
+  return base::ResetAndReturn(&callback_);
+}
+
+}  // namespace cc