Reland with a virtual destructor.

Use XFixes to update the clipboard sequence number.

BUG=73478
TEST=manual testing

Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=109528

Review URL: http://codereview.chromium.org/8501002

git-svn-id: http://src.chromium.org/svn/trunk/src/build@109537 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

linux/system.gyp

@@ -327,6 +327,27 @@
         }],
       ],
     },
+    {
+      'target_name': 'xfixes',
+      'type': 'none',
+      'conditions': [
+        ['_toolset=="target"', {
+          'direct_dependent_settings': {
+            'cflags': [
+              '<!@(<(pkg-config) --cflags xfixes)',
+            ],
+          },
+          'link_settings': {
+            'ldflags': [
+              '<!@(<(pkg-config) --libs-only-L --libs-only-other xfixes)',
+            ],
+            'libraries': [
+              '<!@(<(pkg-config) --libs-only-l xfixes)',
+            ],
+          },
+        }],
+      ],
+    },
     {
       'target_name': 'libgcrypt',
       'type': 'none',