Use Xvfb in isolated testing only if use_x11 is set

chrome/browser_tests.isolate

Index: chrome/browser_tests.isolate
diff --git a/chrome/browser_tests.isolate b/chrome/browser_tests.isolate
index 49569770c2c9d93d29f811450bf11d9f5d2595e6..b451d75e9c441e4cacab358d69356bd4db934b29 100644
--- a/chrome/browser_tests.isolate
+++ b/chrome/browser_tests.isolate
@@ -3,7 +3,18 @@
 # found in the LICENSE file.
 {
   'conditions': [
-    ['OS=="linux"', {
+    ['use_x11==0', {
+      'variables': {
+        'command': [
+          '../testing/test_env.py',
+          '<(PRODUCT_DIR)/browser_tests<(EXECUTABLE_SUFFIX)',
+          '--test-launcher-bot-mode',
+          '--asan=<(asan)',
+          '--lsan=<(lsan)',
+        ],
+      },
+    }],
+    ['use_x11==1', {
       'variables': {
         'command': [
           '../testing/xvfb.py',
@@ -15,16 +26,16 @@
         ],
         'files': [
           '../testing/xvfb.py',
-          '<(PRODUCT_DIR)/libclearkeycdm.so',
-          '<(PRODUCT_DIR)/libclearkeycdmadapter.so',
-          '<(PRODUCT_DIR)/libppapi_tests.so',
+          '<(PRODUCT_DIR)/xdisplaycheck<(EXECUTABLE_SUFFIX)',
         ],
       },
     }],
-    ['OS=="linux" and use_ozone==0', {
+    ['OS=="linux"', {
       'variables': {
         'files': [
-          '<(PRODUCT_DIR)/xdisplaycheck<(EXECUTABLE_SUFFIX)',
+          '<(PRODUCT_DIR)/libclearkeycdm.so',
+          '<(PRODUCT_DIR)/libclearkeycdmadapter.so',
+          '<(PRODUCT_DIR)/libppapi_tests.so',
         ],
       },
     }],
@@ -158,17 +169,6 @@
         ],
       },
     }],
-    ['OS=="mac" or OS=="win"', {
-      'variables': {
-        'command': [
-          '../testing/test_env.py',
-          '<(PRODUCT_DIR)/browser_tests<(EXECUTABLE_SUFFIX)',
-          '--test-launcher-bot-mode',
-          '--asan=<(asan)',
-          '--lsan=<(lsan)',
-        ],
-      },
-    }],
     ['OS=="win"', {
       'variables': {
         'files': [