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" {
 
+const size_t kWindowsPageSize = 4096;
+const size_t kMaxWindowsAllocation =
+    std::numeric_limits<int>::max() - kWindowsPageSize;
 HANDLE win_heap;
 
-bool win_heap_init(bool use_lfh) {
-  win_heap = HeapCreate(0, 0, 0);
+bool win_heap_init() {
+  win_heap = static_cast<HANDLE>(GetProcessHeap());

[cpu_(ooo_6.6-7.5), 2015/01/07 17:25:26]

use http://msdn.microsoft.com/en-us/library/csd157zx.aspx ?

so you don't need that global.

also if we keep the LFH setting here we need to remove the one I added.

[Will Harris, 2015/01/07 17:29:37]

yes I was going to use _get_heap_handle, but for some reason this is
re-implemented in the shim

https://code.google.com/p/chromium/codesearch#chromium/src/base/allocator/all...

I checked the CRT source and _get_heap_handle just calls down into
GetProcessHeap().

   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.
-  }
+  ULONG enable_lfh = 2;
+  // NOTE: Setting LFH may fail.  Vista already has it enabled.
+  //       And under the debugger, it won't use LFH.  So we
+  //       ignore any errors.
+  HeapSetInformation(win_heap, HeapCompatibilityInformation, &enable_lfh,
+                     sizeof(enable_lfh));
 
   return true;
 }
 
 void* win_heap_malloc(size_t size) {
-  return HeapAlloc(win_heap, 0, size);
+  if (size < kMaxWindowsAllocation)
+    return HeapAlloc(win_heap, 0, size);
+  return NULL;
 }
 
 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);
+  if (size < kMaxWindowsAllocation)

[cpu_(ooo_6.6-7.5), 2015/01/07 17:25:26]

if (size > kMaxWindowsAllocation)
  return NULL;

return HeapRealloc(..);

+    return HeapReAlloc(win_heap, 0, ptr, size);
+  return NULL;
 }
 
 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*);
@@ skipping 15 matching lines @@
   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"