Experiment: enable TCMalloc on Linux by default.

chrome/chrome.gyp

 # Copyright (c) 2009 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.
 
 {
   'variables': {
     'chromium_code': 1,
 
     'variables': {
       'version_py_path': 'tools/build/version.py',
@@ skipping 3555 matching lines @@
                 'tools/build/linux/sed.sh',
                 'app/resources/manpage.1.in',
                 '<@(_outputs)',
                 '-e', 's/@@NAME@@/<(name)/',
                 '-e', 's/@@FILENAME@@/<(filename)/',
                 '-e', 's/@@CONFDIR@@/<(confdir)/',
               ],
               'message': 'Generating manpage'
             },
           ],
+          'conditions': [
+            [ 'linux_use_tcmalloc==1', {
+                'dependencies': [
+                  '../third_party/tcmalloc/tcmalloc.gyp:tcmalloc',
+                ],
+              },
+            ],
+          ],
           'dependencies': [
             # On Linux, link the dependencies (libraries) that make up actual
             # Chromium functionality directly into the executable.
             '<@(chromium_dependencies)',
             # Needed for chrome_dll_main.cc #include of gtk/gtk.h
             '../build/linux/system.gyp:gtk',
           ],
           'sources': [
             'app/chrome_dll_main.cc',
             'app/chrome_dll_resource.h',
@@ skipping 3466 matching lines @@
       ]
     }],
   ],  # 'conditions'
 }
 
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 # tab-width:2
 # indent-tabs-mode:nil
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