Move implementation from header to source.

base/weak_ptr.cc

Index: base/weak_ptr.cc
diff --git a/base/weak_ptr.cc b/base/weak_ptr.cc
new file mode 100644
index 0000000000000000000000000000000000000000..2c8f5aa019880b0ee8a743f44f93f3dabce1cc23
--- /dev/null
+++ b/base/weak_ptr.cc
@@ -0,0 +1,65 @@
+// Copyright (c) 2010 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/weak_ptr.h"
+
+namespace base {
+namespace internal {
+
+WeakReference::Flag::Flag(Flag** handle) : handle_(handle) {
+}
+
+WeakReference::Flag::~Flag() {
+  if (handle_)
+    *handle_ = NULL;
+}
+
+void WeakReference::Flag::AddRef() {
+  DCHECK(CalledOnValidThread());
+  RefCounted<Flag>::AddRef();
+}
+
+void WeakReference::Flag::Release() {
+  DCHECK(CalledOnValidThread());
+  RefCounted<Flag>::Release();
+}
+
+WeakReference::WeakReference() {
+}
+
+WeakReference::WeakReference(Flag* flag) : flag_(flag) {
+}
+
+bool WeakReference::is_valid() const {
+  return flag_ && flag_->is_valid();
+}
+
+WeakReferenceOwner::WeakReferenceOwner() : flag_(NULL) {
+}
+
+WeakReferenceOwner::~WeakReferenceOwner() {
+  Invalidate();
+}
+
+WeakReference WeakReferenceOwner::GetRef() const {
+  if (!flag_)
+    flag_ = new WeakReference::Flag(&flag_);
+  return WeakReference(flag_);
+}
+
+void WeakReferenceOwner::Invalidate() {
+  if (flag_) {
+    flag_->Invalidate();
+    flag_ = NULL;
+  }
+}
+
+WeakPtrBase::WeakPtrBase() {
+}
+
+WeakPtrBase::WeakPtrBase(const WeakReference& ref) : ref_(ref) {
+}
+
+}  // namespace internal
+}  // namespace base