tcmalloc: Use C++11 atomics where appropriate.

base/allocator/BUILD.gn

 # Copyright (c) 2013 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.
 
 import("//build/config/allocator.gni")
 import("//build/config/compiler/compiler.gni")
 
 declare_args() {
   # Provide a way to force disable debugallocation in Debug builds,
   # e.g. for profiling (it's more rare to profile Debug builds,
@@ skipping 104 matching lines @@
       # and checked in.
       "$tcmalloc_dir/src/config.h",
       "$tcmalloc_dir/src/config_android.h",
       "$tcmalloc_dir/src/config_linux.h",
       "$tcmalloc_dir/src/config_win.h",
 
       # tcmalloc native and forked files.
       "$tcmalloc_dir/src/base/abort.cc",
       "$tcmalloc_dir/src/base/abort.h",
       "$tcmalloc_dir/src/base/arm_instruction_set_select.h",
-      "$tcmalloc_dir/src/base/atomicops-internals-arm-generic.h",
-      "$tcmalloc_dir/src/base/atomicops-internals-arm-v6plus.h",
-      "$tcmalloc_dir/src/base/atomicops-internals-linuxppc.h",
       "$tcmalloc_dir/src/base/atomicops-internals-macosx.h",
       "$tcmalloc_dir/src/base/atomicops-internals-windows.h",
-      "$tcmalloc_dir/src/base/atomicops-internals-x86.cc",
-      "$tcmalloc_dir/src/base/atomicops-internals-x86.h",
       "$tcmalloc_dir/src/base/atomicops.h",
+      "$tcmalloc_dir/src/base/atomicops_internals_portable.h",
       "$tcmalloc_dir/src/base/basictypes.h",
       "$tcmalloc_dir/src/base/commandlineflags.h",
       "$tcmalloc_dir/src/base/cycleclock.h",
 
       # We don't list dynamic_annotations.c since its copy is already
       # present in the dynamic_annotations target.
       "$tcmalloc_dir/src/base/elf_mem_image.cc",
       "$tcmalloc_dir/src/base/elf_mem_image.h",
       "$tcmalloc_dir/src/base/linuxthreads.cc",
       "$tcmalloc_dir/src/base/linuxthreads.h",
@@ skipping 125 matching lines @@
     # Make sure the allocation library is optimized as much as possible when
     # we"re in release mode.
     if (!is_debug) {
       configs -= [ "//build/config/compiler:default_optimization" ]
       configs += [ "//build/config/compiler:optimize_max" ]
     }
 
     deps += [ "//base/third_party/dynamic_annotations" ]
   }
 }  # !is_android