Fix AV after moving a LinkedList.

src/gpgmm/utils/LinkedList.h

@@ -175,12 +175,16 @@ namespace gpgmm {
             // If any LinkNodes still exist in the LinkedList, there will be outstanding references
             // to root_ even after it has been freed. We should remove root_ from the list to
             // prevent any future access.
-            root_.RemoveFromList();
+            if (root_.IsInList()) {
+                root_.RemoveFromList();
+            }
         }
 
         // Using LinkedList in std::vector or STL container requires the move constructor to not
         // throw.
-        LinkedList(LinkedList&& other) noexcept : root_(std::move(other.root_)) {
+        LinkedList(LinkedList&& other) noexcept
+            : root_(std::move(other.root_)), size_(other.size_) {
+            other.size_ = 0;
         }
 
         // Appends |e| to the end of the linked list.

src/tests/unittests/LinkedListTests.cpp

@@ -81,3 +81,22 @@ TEST(LinkedListTests, Clear) {
     EXPECT_TRUE(list.empty());
     EXPECT_EQ(list.size(), 0u);
 }
+
+TEST(LinkedListTests, Move) {
+    LinkNode<FakeObject>* objectInFirstList = new FakeObject();
+
+    LinkedList<FakeObject> firstList;
+    firstList.push_back(objectInFirstList);
+    EXPECT_EQ(firstList.size(), 1u);
+    EXPECT_FALSE(firstList.empty());
+
+    EXPECT_EQ(firstList.head(), objectInFirstList);
+    EXPECT_EQ(firstList.tail(), objectInFirstList);
+
+    LinkedList<FakeObject> secondList(std::move(firstList));
+    EXPECT_EQ(secondList.size(), 1u);
+    EXPECT_FALSE(secondList.empty());
+
+    EXPECT_EQ(secondList.head(), objectInFirstList);
+    EXPECT_EQ(secondList.tail(), objectInFirstList);
+}