[tracing] Optimize AllocationRegister and increase max backtrace depth.

base/trace_event/heap_profiler_allocation_register_win.cc

 // 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.
 
 #include "base/trace_event/heap_profiler_allocation_register.h"
 
 #include <windows.h>
 #include <stddef.h>
 
 #include "base/bits.h"
 #include "base/logging.h"
 #include "base/process/process_metrics.h"
 
 namespace base {
 namespace trace_event {
+namespace internal {
 
 namespace {
 size_t GetGuardSize() {
   return GetPageSize();
 }
 }
 
-// static
-void* AllocationRegister::AllocateVirtualMemory(size_t size) {
+void* AllocateGuardedVirtualMemory(size_t size) {
   size = bits::Align(size, GetPageSize());
 
   // Add space for a guard page at the end.
   size_t map_size = size + GetGuardSize();
 
   // Reserve the address space. This does not make the memory usable yet.
   void* addr = VirtualAlloc(nullptr, map_size, MEM_RESERVE, PAGE_NOACCESS);
 
   PCHECK(addr != nullptr);
 
   // Commit the non-guard pages as read-write memory.
   void* result = VirtualAlloc(addr, size, MEM_COMMIT, PAGE_READWRITE);
 
   PCHECK(result != nullptr);
 
   // Mark the last page of the allocated address space as guard page. (NB: The
   // |PAGE_GUARD| flag is not the flag to use here, that flag can be used to
   // detect and intercept access to a certain memory region. Accessing a
   // |PAGE_NOACCESS| page will raise a general protection fault.) The
   // read/write accessible space is still at least |min_size| bytes.
   void* guard_addr =
       reinterpret_cast<void*>(reinterpret_cast<uintptr_t>(addr) + size);
   result = VirtualAlloc(guard_addr, GetGuardSize(), MEM_COMMIT, PAGE_NOACCESS);
   PCHECK(result != nullptr);
 
   return addr;
 }
 
-// static
-void AllocationRegister::FreeVirtualMemory(void* address,
-                                           size_t allocated_size) {
+void FreeGuardedVirtualMemory(void* address, size_t allocated_size) {
   // For |VirtualFree|, the size passed with |MEM_RELEASE| mut be 0. Windows
   // automatically frees the entire region that was reserved by the
   // |VirtualAlloc| with flag |MEM_RESERVE|.
   VirtualFree(address, 0, MEM_RELEASE);
 }
 
+}  // namespace internal
 }  // namespace trace_event
 }  // namespace base