Use Xvfb in isolated testing only if use_x11 is set

chrome/sync_integration_tests.isolate

Index: chrome/sync_integration_tests.isolate
diff --git a/chrome/sync_integration_tests.isolate b/chrome/sync_integration_tests.isolate
index 3c5e0e1f544455dd064880af90c08b28dbb7e507..74ea1b9e5db350f15bcc9931a980fff5ffa82c6e 100644
--- a/chrome/sync_integration_tests.isolate
+++ b/chrome/sync_integration_tests.isolate
@@ -3,7 +3,7 @@
 # found in the LICENSE file.
 {
   'conditions': [
-    ['OS=="linux"', {
+    ['OS=="linux" and use_x11==1', {
       'variables': {
         'command': [
           '../testing/xvfb.py',
@@ -14,15 +14,15 @@
         'files': [
           '../testing/test_env.py',
           '../testing/xvfb.py',
-          '<(PRODUCT_DIR)/libffmpegsumo.so',
-          '<(PRODUCT_DIR)/libosmesa.so',
+          '<(PRODUCT_DIR)/xdisplaycheck<(EXECUTABLE_SUFFIX)',
         ],
       },
     }],
-    ['OS=="linux" and use_ozone==0', {
+    ['OS=="linux"', {
       'variables': {
         'files': [
-          '<(PRODUCT_DIR)/xdisplaycheck<(EXECUTABLE_SUFFIX)',
+          '<(PRODUCT_DIR)/libffmpegsumo.so',
+          '<(PRODUCT_DIR)/libosmesa.so',
         ],
       },
     }],
@@ -49,7 +49,7 @@
         ],
       },
     }],
-    ['OS=="mac" or OS=="win"', {
+    ['OS=="mac" or OS=="win" or use_ozone==1', {
       'variables': {
         'command': [
           '<(PRODUCT_DIR)/sync_integration_tests<(EXECUTABLE_SUFFIX)',