Make base::WeakPtr moveable.

base/memory/weak_ptr_unittest.cc

Index: base/memory/weak_ptr_unittest.cc
diff --git a/base/memory/weak_ptr_unittest.cc b/base/memory/weak_ptr_unittest.cc
index eb3a4b249c140528bc7168c4dff6bdf806d4317f..ebcf33c57ec3637407e4246de66159d033562d4e 100644
--- a/base/memory/weak_ptr_unittest.cc
+++ b/base/memory/weak_ptr_unittest.cc
@@ -203,6 +203,16 @@ TEST(WeakPtrFactoryTest, Comparison) {
   EXPECT_EQ(ptr.get(), ptr2.get());
 }
 
+TEST(WeakPtrFactoryTest, Move) {
+  int data;
+  WeakPtrFactory<int> factory(&data);
+  WeakPtr<int> ptr = factory.GetWeakPtr();
+  WeakPtr<int> ptr2 = factory.GetWeakPtr();
+  WeakPtr<int> ptr3 = std::move(ptr2);
+  EXPECT_NE(ptr.get(), ptr2.get());
+  EXPECT_EQ(ptr.get(), ptr3.get());
+}
+
 TEST(WeakPtrFactoryTest, OutOfScope) {
   WeakPtr<int> ptr;
   EXPECT_EQ(nullptr, ptr.get());