Enable TCMalloc on Linux by default.

build/common.gypi

 # Copyright (c) 2010 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.
 
 # IMPORTANT:
 # Please don't directly include this file if you are building via gyp_chromium,
 # since gyp_chromium is automatically forcing its inclusion.
 {
   'variables': {
     # .gyp files or targets should set chromium_code to 1 if they build
@@ skipping 185 matching lines @@
     # sandbox the zygote process and, thus, all renderer processes.
     'linux_sandbox_path%': '',
 
     # Set this to true to enable SELinux support.
     'selinux%': 0,
 
     # Strip the binary after dumping symbols.
     'linux_strip_binary%': 0,
 
     # Enable TCMalloc.
-    'linux_use_tcmalloc%': 0,
+    'linux_use_tcmalloc%': 1,
 
     # Set to select the Title Case versions of strings in GRD files.
     'use_titlecase_in_grd_files%': 0,
 
     # Used to disable Native Client at compile time, for platforms where it
     # isn't supported
     'disable_nacl%': 0,
 
     # Set Thumb compilation flags.
     'arm_thumb%': 0,
@@ skipping 1021 matching lines @@
     # and therefore SYMROOT, needs to be set at the project level.
     'SYMROOT': '<(DEPTH)/xcodebuild',
   },
 }
 
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 # tab-width:2
 # indent-tabs-mode:nil
 # End:
 # vim: set expandtab tabstop=2 shiftwidth=2: