Tag all tracked objects, including Tasks, with the program counter at the site of FROM_HERE.

base/debug/alias.cc

+// Copyright (c) 2011 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/debug/alias.h"
+#include "build/build_config.h"
+
+namespace base {
+namespace debug {
+
+// Prevent MSVC link time code generation from inlining this function. This
+// could render the referenced variable unaliased.
+#if defined(COMPILER_MSVC)
+#pragma warning(disable: 4748)
+#pragma optimize("", off)
+#endif
+
+void Alias(const void* var) {
+}
+
+#if defined(COMPILER_MSVC)
+#pragma optimize("", on)
+#pragma warning(default: 4748)
+#endif
+
+}  // namespace debug
+}  // namespace base