Lands http://codereview.chromium.org/3166002 for bryeung:

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 43 matching lines @@
           }, {  # OS!="linux"
             'host_arch%': 'ia32',
           }],
         ],
 
         # Whether we're building a ChromeOS build.  We set the initial
         # value at this level of nesting so it's available for the
         # toolkit_views test below.
         'chromeos%': '0',
 
+        # Disable touch support by default.
+        'touchui%': 0,
+
         # To do a shared build on linux we need to be able to choose between
         # type static_library and shared_library. We default to doing a static
         # build but you can override this with "gyp -Dlibrary=shared_library"
         # or you can add the following line (without the #) to
         # ~/.gyp/include.gypi {'variables': {'library': 'shared_library'}}
         # to compile as shared by default
         'library%': 'static_library',
       },
 
-      # Set default value of toolkit_views on for Windows and Chrome OS.
+      # Set default value of toolkit_views on for Windows, Chrome OS
+      # and the touch UI.
       # We set it at this level of nesting so the value is available for
       # other conditionals below.
       'conditions': [
-        ['OS=="win" or chromeos==1', {
+        ['OS=="win" or chromeos==1 or touchui==1', {
           'toolkit_views%': 1,
         }, {
           'toolkit_views%': 0,
         }],
       ],
 
       'host_arch%': '<(host_arch)',
 
       # Default architecture we're building for is the architecture we're
       # building on.
       'target_arch%': '<(host_arch)',
 
       # We do want to build Chromium with Breakpad support in certain
       # situations. I.e. for Chrome bot.
       'linux_chromium_breakpad%': 0,
       # And if we want to dump symbols.
       'linux_chromium_dump_symbols%': 0,
       # Also see linux_strip_binary below.
 
-      # Copy conditionally-set chromeos variable out one scope.
+      # Copy conditionally-set chromeos and touchui variables out one scope.
       'chromeos%': '<(chromeos)',
+      'touchui%': '<(touchui)',
 
       # This variable tells WebCore.gyp and JavaScriptCore.gyp whether they are
       # are built under a chromium full build (1) or a webkit.org chromium
       # build (0).
       'inside_chromium_build%': 1,
 
       # Set to 1 to enable fast builds. It disables debug info for fastest
       # compilation.
       'fastbuild%': 0,
 
@@ skipping 30 matching lines @@
     },
 
     # Define branding and buildtype on the basis of their settings within the
     # variables sub-dict above, unless overridden.
     'branding%': '<(branding)',
     'buildtype%': '<(buildtype)',
     'target_arch%': '<(target_arch)',
     'host_arch%': '<(host_arch)',
     'toolkit_views%': '<(toolkit_views)',
     'chromeos%': '<(chromeos)',
+    'touchui%': '<(touchui)',
     'inside_chromium_build%': '<(inside_chromium_build)',
     'fastbuild%': '<(fastbuild)',
     'linux_fpic%': '<(linux_fpic)',
     'python_ver%': '<(python_ver)',
     'armv7%': '<(armv7)',
     'arm_neon%': '<(arm_neon)',
     'sysroot%': '<(sysroot)',
     'disable_sse2%': '<(disable_sse2)',
     'remoting%': '<(remoting)',
     'library%': '<(library)',
@@ skipping 214 matching lines @@
     # NOTE: When these end up in the Mac bundle, we need to replace '-' for '_'
     # so Cocoa is happy (http://crbug.com/20441).
     'locales': [
       'am', 'ar', 'bg', 'bn', 'ca', 'cs', 'da', 'de', 'el', 'en-GB',
       'en-US', 'es-419', 'es', 'et', 'fi', 'fil', 'fr', 'gu', 'he',
       'hi', 'hr', 'hu', 'id', 'it', 'ja', 'kn', 'ko', 'lt', 'lv',
       'ml', 'mr', 'nb', 'nl', 'pl', 'pt-BR', 'pt-PT', 'ro', 'ru',
       'sk', 'sl', 'sr', 'sv', 'sw', 'ta', 'te', 'th', 'tr', 'uk',
       'vi', 'zh-CN', 'zh-TW',
     ],
-    
-    # Disable touch support by default.
-    'touchui%': 0,
   },
   'target_defaults': {
     'variables': {
       # The condition that operates on chromium_code is in a target_conditions
       # section, and will not have access to the default fallback value of
       # chromium_code at the top of this file, or to the chromium_code
       # variable placed at the root variables scope of .gyp files, because
       # those variables are not set at target scope.  As a workaround,
       # if chromium_code is not set at target scope, define it in target scope
       # to contain whatever value it has during early variable expansion.
@@ skipping 1041 matching lines @@
     # and therefore SYMROOT, needs to be set at the project level.
     'SYMROOT': '<(DEPTH)/xcodebuild',
   },
 }
 
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