Remove tcmalloc when not being used. Restore shim on Windows.

base/allocator/win_allocator.cc

-// Copyright (c) 2012 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.
-
-// This is a simple allocator based on the windows heap.
-
-extern "C" {
-
-HANDLE win_heap;
-
-bool win_heap_init(bool use_lfh) {
-  win_heap = HeapCreate(0, 0, 0);
-  if (win_heap == NULL)
-    return false;
-
-  if (use_lfh) {
-    ULONG enable_lfh = 2;
-    HeapSetInformation(win_heap, HeapCompatibilityInformation,
-                       &enable_lfh, sizeof(enable_lfh));
-    // NOTE: Setting LFH may fail.  Vista already has it enabled.
-    //       And under the debugger, it won't use LFH.  So we
-    //       ignore any errors.
-  }
-
-  return true;
-}
-
-void* win_heap_malloc(size_t size) {
-  return HeapAlloc(win_heap, 0, size);
-}
-
-void win_heap_free(void* size) {
-  HeapFree(win_heap, 0, size);
-}
-
-void* win_heap_realloc(void* ptr, size_t size) {
-  if (!ptr)
-    return win_heap_malloc(size);
-  if (!size) {
-    win_heap_free(ptr);
-    return NULL;
-  }
-  return HeapReAlloc(win_heap, 0, ptr, size);
-}
-
-size_t win_heap_msize(void* ptr) {
-  return HeapSize(win_heap, 0, ptr);
-}
-
-void* win_heap_memalign(size_t alignment, size_t size) {
-  // Reserve enough space to ensure we can align and set aligned_ptr[-1] to the
-  // original allocation for use with win_heap_memalign_free() later.
-  size_t allocation_size = size + (alignment - 1) + sizeof(void*);
-
-  // Check for overflow.  Alignment and size are checked in allocator_shim.
-  DCHECK_LT(size, allocation_size);
-  DCHECK_LT(alignment, allocation_size);
-
-  // Since we're directly calling the allocator function, before OOM handling,
-  // we need to NULL check to ensure the allocation succeeded.
-  void* ptr = win_heap_malloc(allocation_size);
-  if (!ptr)
-    return ptr;
-
-  char* aligned_ptr = static_cast<char*>(ptr) + sizeof(void*);
-  aligned_ptr +=
-      alignment - reinterpret_cast<uintptr_t>(aligned_ptr) & (alignment - 1);
-
-  reinterpret_cast<void**>(aligned_ptr)[-1] = ptr;
-  return aligned_ptr;
-}
-
-void win_heap_memalign_free(void* ptr) {
-  if (ptr)
-    win_heap_free(static_cast<void**>(ptr)[-1]);
-}
-
-}  // extern "C"