aura: Make 'ui' buildable without gtk.

build/linux/system.gyp

 # Copyright (c) 2011 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.
 
 {
   'conditions': [
     ['sysroot!=""', {
       'variables': {
         'pkg-config': './pkg-config-wrapper "<(sysroot)"',
       },
@@ skipping 489 matching lines @@
           },
         }],
         ['chromeos==1', {
           'link_settings': {
             'libraries': [ '-lXtst' ]
           }
         }],
       ],
     },
     {
+      'target_name': 'pangocairo',
+      'type': 'settings',
+      'toolsets': ['host', 'target'],
+      'conditions': [
+        ['_toolset=="target"', {
+          'direct_dependent_settings': {
+            'cflags': [
+              '<!@(<(pkg-config) --cflags pangocairo)',
+            ],
+          },
+          'link_settings': {
+            'ldflags': [
+              '<!@(<(pkg-config) --libs-only-L --libs-only-other pangocairo)',
+            ],
+            'libraries': [
+              '<!@(<(pkg-config) --libs-only-l pangocairo)',
+            ],
+          },
+        }, {
+          'direct_dependent_settings': {
+            'cflags': [
+              '<!@(pkg-config --cflags pangocairo)',
+            ],
+          },
+          'link_settings': {
+            'ldflags': [
+              '<!@(pkg-config --libs-only-L --libs-only-other pangocairo)',
+            ],
+            'libraries': [
+              '<!@(pkg-config --libs-only-l pangocairo)',
+            ],
+          },
+        }],
+      ],
+    },
+    {
       'target_name': 'libresolv',
       'type': 'settings',
       'link_settings': {
         'libraries': [
           '-lresolv',
         ],
       },
     },
     {
       'target_name': 'ibus',
@@ skipping 39 matching lines @@
             ],
             'libraries': [
               '<!@(<(pkg-config) --libs-only-l wayland-client wayland-egl xkbcommon)',
             ],
           },
         }],
       ],
     },
   ],
 }