Linux: make cups (common unix printing system) dependency optional.

chrome/chrome.gyp

 # 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.
 {
   'variables': {
     'chromium_code': 1,
 
     'variables': {
       'version_py_path': 'tools/build/version.py',
       'version_path': 'VERSION',
@@ skipping 1079 matching lines @@
         'service/gaia/service_gaia_authenticator.cc',
         'service/gaia/service_gaia_authenticator.h',
         'service/net/service_network_change_notifier_thread.cc',
         'service/net/service_network_change_notifier_thread.h',
         'service/net/service_url_request_context.cc',
         'service/net/service_url_request_context.h',
       ],
       'include_dirs': [
         '..',
       ],
+      'variables': {
+        'conditions': [
+          ['OS=="linux" and chromeos==0 and target_arch!="arm"', {
+            'use_cups%': 1,
+          }, {
+            'use_cups%': 0,
+          }],
+        ],
+      },
       'conditions': [
         ['OS=="win"', {
           'defines': [
             # CP_PRINT_SYSTEM_AVAILABLE disables default dummy implementation
             # of cloud print system, and allows to use custom implementaiton.
             'CP_PRINT_SYSTEM_AVAILABLE',
           ],
           'sources': [
             'service/cloud_print/print_system_win.cc',
           ],
         }],
         ['OS=="linux"', {
           'dependencies': [
             '../build/linux/system.gyp:gtk',
           ],
         }],
-        ['OS=="linux" and chromeos==0 and target_arch!="arm"', {
+        ['use_cups==1', {
           'link_settings': {
             'libraries': [
               '-lcups',
               '-lgcrypt',
               '-lgnutls',
             ],
           },
           'defines': [
             # CP_PRINT_SYSTEM_AVAILABLE disables default dummy implementation
             # of cloud print system, and allows to use custom implementaiton.
@@ skipping 731 matching lines @@
       }],  # targets
     }],  # OS=="linux" or OS=="freebsd" or OS=="openbsd" or OS=="solaris"
   ],  # 'conditions'
 }
 
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