Make base::WeakPtr moveable.

base/memory/weak_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.
 
 // Weak pointers are pointers to an object that do not affect its lifetime,
 // and which may be invalidated (i.e. reset to nullptr) by the object, or its
 // owner, at any time, most commonly when the object is about to be deleted.
 
 // Weak pointers are useful when an object needs to be accessed safely by one
 // or more objects other than its owner, and those callers can cope with the
@@ skipping 91 matching lines @@
    private:
     friend class base::RefCountedThreadSafe<Flag>;
 
     ~Flag();
 
     SequenceChecker sequence_checker_;
     bool is_valid_;
   };
 
   WeakReference();
-  WeakReference(const WeakReference& other);
   explicit WeakReference(const Flag* flag);
   ~WeakReference();
 
+  WeakReference(WeakReference&& other);
+  WeakReference(const WeakReference& other);
+  WeakReference& operator=(WeakReference&& other) = default;
+  WeakReference& operator=(const WeakReference& other) = default;
+
   bool is_valid() const;
 
  private:
   scoped_refptr<const Flag> flag_;
 };
 
 class BASE_EXPORT WeakReferenceOwner {
  public:
   WeakReferenceOwner();
   ~WeakReferenceOwner();
@@ skipping 12 matching lines @@
 
 // This class simplifies the implementation of WeakPtr's type conversion
 // constructor by avoiding the need for a public accessor for ref_.  A
 // WeakPtr<T> cannot access the private members of WeakPtr<U>, so this
 // base class gives us a way to access ref_ in a protected fashion.
 class BASE_EXPORT WeakPtrBase {
  public:
   WeakPtrBase();
   ~WeakPtrBase();
 
+  WeakPtrBase(const WeakPtrBase& other) = default;
+  WeakPtrBase(WeakPtrBase&& other) = default;
+  WeakPtrBase& operator=(const WeakPtrBase& other) = default;
+  WeakPtrBase& operator=(WeakPtrBase&& other) = default;
+
  protected:
   explicit WeakPtrBase(const WeakReference& ref);
 
   WeakReference ref_;
 };
 
 // This class provides a common implementation of common functions that would
 // otherwise get instantiated separately for each distinct instantiation of
 // SupportsWeakPtr<>.
 class SupportsWeakPtrBase {
@@ skipping 40 matching lines @@
 //     foo->method();
 //
 template <typename T>
 class WeakPtr : public internal::WeakPtrBase {
  public:
   WeakPtr() : ptr_(nullptr) {}
 
   WeakPtr(std::nullptr_t) : ptr_(nullptr) {}
 
   // Allow conversion from U to T provided U "is a" T. Note that this
-  // is separate from the (implicit) copy constructor.
+  // is separate from the (implicit) copy and move constructors.
   template <typename U>
   WeakPtr(const WeakPtr<U>& other) : WeakPtrBase(other), ptr_(other.ptr_) {
   }
+  template <typename U>
+  WeakPtr(WeakPtr<U>&& other) : WeakPtrBase(other), ptr_(other.ptr_) {

[vmpstr, 2016/06/24 00:17:39]

WeakPtrBase(std::move(other))

[Marijn Kruisselbrink, 2016/06/24 00:50:15]

Done

+  }
 
   T* get() const { return ref_.is_valid() ? ptr_ : nullptr; }
 
   T& operator*() const {
     DCHECK(get() != nullptr);
     return *get();
   }
   T* operator->() const {
     DCHECK(get() != nullptr);
     return get();
@@ skipping 118 matching lines @@
 //   base::WeakPtr<Derived> ptr = derived.AsWeakPtr();  // Fails.
 
 template <typename Derived>
 WeakPtr<Derived> AsWeakPtr(Derived* t) {
   return internal::SupportsWeakPtrBase::StaticAsWeakPtr<Derived>(t);
 }
 
 }  // namespace base
 
 #endif  // BASE_MEMORY_WEAK_PTR_H_