Fix -Wshift-negative-value transgression in tcmalloc.

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/buildflag_header.gni")
 import("//build/config/allocator.gni")
 import("//build/config/compiler/compiler.gni")
 
 declare_args() {
   # Provide a way to force disable debugallocation in Debug builds,
@@ skipping 47 matching lines @@
     defines += [ "TCMALLOC_DONT_REPLACE_SYSTEM_ALLOC" ]
   }
   if (is_clang) {
     cflags = [
       # tcmalloc initializes some fields in the wrong order.
       "-Wno-reorder",
 
       # tcmalloc contains some unused local template specializations.
       "-Wno-unused-function",
 
-      # tcmalloc uses COMPILE_ASSERT without static_assert but with
-      # typedefs.
+      # tcmalloc uses COMPILE_ASSERT without static_assert but with typedefs.
       "-Wno-unused-local-typedefs",
 
-      # for magic2_ in debugallocation.cc (only built in Debug builds)
-      # typedefs.
+      # for magic2_ in debugallocation.cc (only built in Debug builds) typedefs.
       "-Wno-unused-private-field",
-
-      # base/basictypes.h's kint64min definition shifts a negative value around,
-      # which is undefined behavior. TODO(thakis): Try to get that fixed.
-      "-Wno-shift-negative-value",
     ]
   } else {
     cflags = []
   }
 
   if (is_linux || is_android) {
     # We enable all warnings by default, but upstream disables a few.
     # Keep "-Wno-*" flags in sync with upstream by comparing against:
     # http://code.google.com/p/google-perftools/source/browse/trunk/Makefile.am
     cflags += [
@@ skipping 220 matching lines @@
     "-Wl,-wrap,calloc",
     "-Wl,-wrap,free",
     "-Wl,-wrap,malloc",
     "-Wl,-wrap,memalign",
     "-Wl,-wrap,posix_memalign",
     "-Wl,-wrap,pvalloc",
     "-Wl,-wrap,realloc",
     "-Wl,-wrap,valloc",
   ]
 }