Replace instances of LINUX2 with OS_CHROMEOS and linux2 with chromeos.

build/common.gypi

 # 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': {
     # .gyp files should set chromium_code to 1 if they build Chromium-specific
     # code, as opposed to external code.  This variable is used to control
     # such things as the set of warnings to enable, and whether warnings are
     # treated as errors.
@@ skipping 62 matching lines @@
     'msvs_debug_link_incremental%': '2',
 
     # The architecture that we're building on.
     'target_arch%': 'ia32',
 
     # By default linux does not use views. To turn on views in Linux
     # set the variable GYP_DEFINES to "toolkit_views=1", or modify
     # ~/.gyp/include.gypi .
     'toolkit_views%': 0,
 
-    'linux2%': 0,
+    'chromeos%': 0,
 
     'chrome_personalization%': 0,
   },
   'target_defaults': {
     'conditions': [
       ['branding=="Chrome"', {
         'defines': ['GOOGLE_CHROME_BUILD'],
         'conditions': [
           ['OS=="linux"', {
             'cflags': [ '-gstabs' ],
           }],
         ],
       }, {  # else: branding!="Chrome"
         'defines': ['CHROMIUM_BUILD'],
       }],
       ['toolkit_views==1', {
         'defines': ['TOOLKIT_VIEWS=1'],
       }],
-      ['linux2==1', {
-        'defines': ['LINUX2=1'],
+      ['chromeos==1', {
+        'defines': ['OS_CHROMEOS=1'],
       }],
       ['chrome_personalization==1', {
         'defines': ['CHROME_PERSONALIZATION=1'],
       }],
       ['coverage!=0', {
         'conditions': [
           ['OS=="mac"', {
             'xcode_settings': {
               'GCC_INSTRUMENT_PROGRAM_FLOW_ARCS': 'YES',
               'GCC_GENERATE_TEST_COVERAGE_FILES': 'YES',
@@ skipping 468 matching lines @@
     # settings in target dicts.  SYMROOT is a special case, because many other
     # Xcode variables depend on it, including variables such as
     # PROJECT_DERIVED_FILE_DIR.  When a source group corresponding to something
     # like PROJECT_DERIVED_FILE_DIR is added to a project, in order for the
     # files to appear (when present) in the UI as actual files and not red
     # red "missing file" proxies, the correct path to PROJECT_DERIVED_FILE_DIR,
     # and therefore SYMROOT, needs to be set at the project level.
     'SYMROOT': '<(DEPTH)/xcodebuild',
   },
 }