Revert of components/metrics: Add runtime memory leak detector

components/metrics/leak_detector/custom_allocator.h

Index: components/metrics/leak_detector/custom_allocator.h
diff --git a/components/metrics/leak_detector/custom_allocator.h b/components/metrics/leak_detector/custom_allocator.h
deleted file mode 100644
index fdbfc779b9f26f47d587d41c27bea15584c203e4..0000000000000000000000000000000000000000
--- a/components/metrics/leak_detector/custom_allocator.h
+++ /dev/null
@@ -1,50 +0,0 @@
-// Copyright 2015 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.
-
-#ifndef COMPONENTS_METRICS_LEAK_DETECTOR_CUSTOM_ALLOCATOR_H_
-#define COMPONENTS_METRICS_LEAK_DETECTOR_CUSTOM_ALLOCATOR_H_
-
-#include <stddef.h>
-
-#include <type_traits>
-
-namespace metrics {
-namespace leak_detector {
-
-// Custom allocator class to be passed to STLAllocator as a template argument.
-//
-// By default, CustomAllocator uses the default allocator (new/delete), but the
-// caller of Initialize ()can provide a pair of alternative alloc/ free
-// functions to use as an external allocator.
-//
-// This is a stateless class, but there is static data within the module that
-// needs to be created and deleted.
-//
-// Not thread-safe.
-class CustomAllocator {
- public:
-  using AllocFunc = std::add_pointer<void*(size_t)>::type;
-  using FreeFunc = std::add_pointer<void(void*, size_t)>::type;
-
-  // Initialize CustomAllocator to use the default allocator.
-  static void Initialize();
-
-  // Initialize CustomAllocator to use the given alloc/free functions.
-  static void Initialize(AllocFunc alloc_func, FreeFunc free_func);
-
-  // Performs any cleanup required, e.g. unset custom functions. Returns true
-  // on success or false if something failed.
-  static bool Shutdown();
-
-  static bool IsInitialized();
-
-  // These functions must match the specifications in STLAllocator.
-  static void* Allocate(size_t size);
-  static void Free(void* ptr, size_t size);
-};
-
-}  // namespace leak_detector
-}  // namespace metrics
-
-#endif  // COMPONENTS_METRICS_LEAK_DETECTOR_CUSTOM_ALLOCATOR_H_