Rationalize linux vs x11 in ui

build/common.gypi

Index: build/common.gypi
diff --git a/build/common.gypi b/build/common.gypi
index 128d1f18e74db850f5e6b0c12a1c725f63fa883d..eb3c74726507c8701e92a29d290b61d05ed13317 100644
--- a/build/common.gypi
+++ b/build/common.gypi
@@ -135,7 +135,7 @@
           }],
 
           # Set toolkit_uses_gtk for the Chromium browser on Linux.
-          ['(OS=="linux" or OS=="freebsd" or OS=="openbsd" or OS=="solaris") and use_aura==0', {
+          ['(OS=="linux" or OS=="freebsd" or OS=="openbsd" or OS=="solaris") and use_aura==0 and use_messagepump_linux==0', {
             'toolkit_uses_gtk%': 1,
           }, {
             'toolkit_uses_gtk%': 0,
@@ -1846,6 +1846,9 @@
       ['use_nss==1', {
         'defines': ['USE_NSS=1'],
       }],
+      ['use_x11==1', {
+        'defines': ['USE_X11=1'],
+      }],
       ['enable_one_click_signin==1', {
         'defines': ['ENABLE_ONE_CLICK_SIGNIN'],
       }],