Add checks to DEBUG mode that no instance of URLRequest or URLFetcher survives the destruction of the IO thread.

This checking is done by introducing a new helper class to base called LeakTracker. Classes that you want to check for leaks just need to extend LeakTracker.

The reason I am picking on URLFetcher / URLRequest, is I believe we have a bug that is making an instance of URLFetcher to outlive the IO thread.

This causes various sorts of badness.

For example:
If URLFetcher survives the IO thread, then URLRequestContext remains referenced and therefore also survives IO thread. In turn HostResolverImpl survives the IO thread, so any outstanding resolve requests are NOT cancelled before the IO thread is decomissioned. So now, when the worker thread doing the DNS resolve finally finishes (assuming it finishes before the rogue URLRequest is destroyed), it post the result to a defunct message loop. KAB00m! (http://crbug.com/15513)

Moreover, I believe we hit this same problem sporadically in AutomationProxyTest.AutocompleteGetSetText -- the test is flaky on the buildbots, and I've seen DCHECKs which suggest it is related to this issue.

BUG=http://crbug.com/18372
Review URL: http://codereview.chromium.org/160447

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@23084 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 245 insertions, 0 deletions

diff --git a/base/linked_list_unittest.cc b/base/linked_list_unittest.cc
new file mode 100644
index 0000000..835d927
--- /dev/null
+++ b/base/linked_list_unittest.cc
@@ -0,0 +1,245 @@
+// Copyright (c) 2009 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/linked_list.h"
+#include "base/basictypes.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace base {
+namespace {
+
+class Node : public LinkNode<Node> {
+ public:
+  explicit Node(int id) : id_(id) {}
+
+  int id() const { return id_; }
+
+ private:
+  int id_;
+};
+
+// Checks that when iterating |list| (either from head to tail, or from
+// tail to head, as determined by |forward|), we get back |node_ids|,
+// which is an array of size |num_nodes|.
+void ExpectListContentsForDirection(const LinkedList<Node>& list,
+  int num_nodes, const int* node_ids, bool forward) {
+  int i = 0;
+  for (const LinkNode<Node>* node = (forward ? list.head() : list.tail());
+       node != list.end();
+       node = (forward ? node->next() : node->previous())) {
+    ASSERT_LT(i, num_nodes);
+    int index_of_id = forward ? i : num_nodes - i - 1;
+    EXPECT_EQ(node_ids[index_of_id], node->value()->id());
+    ++i;
+  }
+  EXPECT_EQ(num_nodes, i);
+}
+
+void ExpectListContents(const LinkedList<Node>& list,
+                        int num_nodes,
+                        const int* node_ids) {
+  {
+    SCOPED_TRACE("Iterating forward (from head to tail)");
+    ExpectListContentsForDirection(list, num_nodes, node_ids, true);
+  }
+  {
+    SCOPED_TRACE("Iterating backward (from tail to head)");
+    ExpectListContentsForDirection(list, num_nodes, node_ids, false);
+  }
+}
+
+TEST(LinkedList, Empty) {
+  LinkedList<Node> list;
+  EXPECT_EQ(list.end(), list.head());
+  EXPECT_EQ(list.end(), list.tail());
+  ExpectListContents(list, 0, NULL);
+}
+
+
+TEST(LinkedList, Append) {
+  LinkedList<Node> list;
+  ExpectListContents(list, 0, NULL);
+
+  Node n1(1);
+  list.Append(&n1);
+
+  EXPECT_EQ(&n1, list.head());
+  EXPECT_EQ(&n1, list.tail());
+  {
+    const int expected[] = {1};
+    ExpectListContents(list, arraysize(expected), expected);
+  }
+
+  Node n2(2);
+  list.Append(&n2);
+
+  EXPECT_EQ(&n1, list.head());
+  EXPECT_EQ(&n2, list.tail());
+  {
+    const int expected[] = {1, 2};
+    ExpectListContents(list, arraysize(expected), expected);
+  }
+
+  Node n3(3);
+  list.Append(&n3);
+
+  EXPECT_EQ(&n1, list.head());
+  EXPECT_EQ(&n3, list.tail());
+  {
+    const int expected[] = {1, 2, 3};
+    ExpectListContents(list, arraysize(expected), expected);
+  }
+}
+
+TEST(LinkedList, RemoveFromList) {
+  LinkedList<Node> list;
+
+  Node n1(1);
+  Node n2(2);
+  Node n3(3);
+  Node n4(4);
+  Node n5(5);
+
+  list.Append(&n1);
+  list.Append(&n2);
+  list.Append(&n3);
+  list.Append(&n4);
+  list.Append(&n5);
+
+  EXPECT_EQ(&n1, list.head());
+  EXPECT_EQ(&n5, list.tail());
+  {
+    const int expected[] = {1, 2, 3, 4, 5};
+    ExpectListContents(list, arraysize(expected), expected);
+  }
+
+  // Remove from the middle.
+  n3.RemoveFromList();
+
+  EXPECT_EQ(&n1, list.head());
+  EXPECT_EQ(&n5, list.tail());
+  {
+    const int expected[] = {1, 2, 4, 5};
+    ExpectListContents(list, arraysize(expected), expected);
+  }
+
+  // Remove from the tail.
+  n5.RemoveFromList();
+
+  EXPECT_EQ(&n1, list.head());
+  EXPECT_EQ(&n4, list.tail());
+  {
+    const int expected[] = {1, 2, 4};
+    ExpectListContents(list, arraysize(expected), expected);
+  }
+
+  // Remove from the head.
+  n1.RemoveFromList();
+
+  EXPECT_EQ(&n2, list.head());
+  EXPECT_EQ(&n4, list.tail());
+  {
+    const int expected[] = {2, 4};
+    ExpectListContents(list, arraysize(expected), expected);
+  }
+
+  // Empty the list.
+  n2.RemoveFromList();
+  n4.RemoveFromList();
+
+  ExpectListContents(list, 0, NULL);
+  EXPECT_EQ(list.end(), list.head());
+  EXPECT_EQ(list.end(), list.tail());
+
+  // Fill the list once again.
+  list.Append(&n1);
+  list.Append(&n2);
+  list.Append(&n3);
+  list.Append(&n4);
+  list.Append(&n5);
+
+  EXPECT_EQ(&n1, list.head());
+  EXPECT_EQ(&n5, list.tail());
+  {
+    const int expected[] = {1, 2, 3, 4, 5};
+    ExpectListContents(list, arraysize(expected), expected);
+  }
+}
+
+TEST(LinkedList, InsertBefore) {
+  LinkedList<Node> list;
+
+  Node n1(1);
+  Node n2(2);
+  Node n3(3);
+  Node n4(4);
+
+  list.Append(&n1);
+  list.Append(&n2);
+
+  EXPECT_EQ(&n1, list.head());
+  EXPECT_EQ(&n2, list.tail());
+  {
+    const int expected[] = {1, 2};
+    ExpectListContents(list, arraysize(expected), expected);
+  }
+
+  n3.InsertBefore(&n2);
+
+  EXPECT_EQ(&n1, list.head());
+  EXPECT_EQ(&n2, list.tail());
+  {
+    const int expected[] = {1, 3, 2};
+    ExpectListContents(list, arraysize(expected), expected);
+  }
+
+  n4.InsertBefore(&n1);
+
+  EXPECT_EQ(&n4, list.head());
+  EXPECT_EQ(&n2, list.tail());
+  {
+    const int expected[] = {4, 1, 3, 2};
+    ExpectListContents(list, arraysize(expected), expected);
+  }
+}
+
+TEST(LinkedList, InsertAfter) {
+  LinkedList<Node> list;
+
+  Node n1(1);
+  Node n2(2);
+  Node n3(3);
+  Node n4(4);
+
+  list.Append(&n1);
+  list.Append(&n2);
+
+  EXPECT_EQ(&n1, list.head());
+  EXPECT_EQ(&n2, list.tail());
+  {
+    const int expected[] = {1, 2};
+    ExpectListContents(list, arraysize(expected), expected);
+  }
+
+  n3.InsertAfter(&n2);
+
+  EXPECT_EQ(&n1, list.head());
+  EXPECT_EQ(&n3, list.tail());
+  {
+    const int expected[] = {1, 2, 3};
+    ExpectListContents(list, arraysize(expected), expected);
+  }
+
+  n4.InsertAfter(&n1);
+
+  EXPECT_EQ(&n1, list.head());
+  EXPECT_EQ(&n3, list.tail());
+  {
+    const int expected[] = {1, 4, 2, 3};
+    ExpectListContents(list, arraysize(expected), expected);
+  }
+}
+
+}  // namespace
+}  // namespace base