Use Xvfb in isolated testing only if use_x11 is set (reland)

ui/base/ui_base_unittests.isolate

Index: ui/base/ui_base_unittests.isolate
diff --git a/ui/base/ui_base_unittests.isolate b/ui/base/ui_base_unittests.isolate
index 5635f358779e00a9a48a98de6aa907b5af747168..6288305f34aa2b0b440aacd663e6d22131826237 100644
--- a/ui/base/ui_base_unittests.isolate
+++ b/ui/base/ui_base_unittests.isolate
@@ -3,25 +3,20 @@
 # found in the LICENSE file.
 {
   'conditions': [
-    ['OS=="linux" or OS=="mac" or OS=="win"', {
+    ['use_x11==0', {
       'variables': {
-        'files': [
+        'command': [
           '../../testing/test_env.py',
-          'test/data/data_pack_unittest/truncated-header.pak',
           '<(PRODUCT_DIR)/ui_base_unittests<(EXECUTABLE_SUFFIX)',
-          '<(PRODUCT_DIR)/ui_test.pak',
-        ],
-      },
-    }],
-    ['OS=="linux" or OS=="win"', {
-      'variables': {
-        'files': [
-          '<(PRODUCT_DIR)/ui/en-US.pak',
-          '<(PRODUCT_DIR)/ui/ui_resources_100_percent.pak',
+          '--brave-new-test-launcher',
+          '--test-launcher-bot-mode',
+          '--asan=<(asan)',
+          '--msan=<(msan)',
+          '--tsan=<(tsan)',
         ],
       },
     }],
-    ['OS=="linux"', {
+    ['use_x11==1', {
       'variables': {
         'command': [
           '../../testing/xvfb.py',
@@ -35,14 +30,32 @@
         ],
         'files': [
           '../../testing/xvfb.py',
-          '<(PRODUCT_DIR)/libosmesa.so',
+          '<(PRODUCT_DIR)/xdisplaycheck<(EXECUTABLE_SUFFIX)',
         ],
       },
     }],
-    ['OS=="linux" and use_ozone==0', {
+    ['OS=="linux" or OS=="mac" or OS=="win"', {
       'variables': {
         'files': [
-          '<(PRODUCT_DIR)/xdisplaycheck<(EXECUTABLE_SUFFIX)',
+          '../../testing/test_env.py',
+          'test/data/data_pack_unittest/truncated-header.pak',
+          '<(PRODUCT_DIR)/ui_base_unittests<(EXECUTABLE_SUFFIX)',
+          '<(PRODUCT_DIR)/ui_test.pak',
+        ],
+      },
+    }],
+    ['OS=="linux" or OS=="win"', {
+      'variables': {
+        'files': [
+          '<(PRODUCT_DIR)/ui/en-US.pak',
+          '<(PRODUCT_DIR)/ui/ui_resources_100_percent.pak',
+        ],
+      },
+    }],
+    ['OS=="linux"', {
+      'variables': {
+        'files': [
+          '<(PRODUCT_DIR)/libosmesa.so',
         ],
       },
     }],
@@ -61,19 +74,6 @@
         ],
       },
     }],
-    ['OS=="mac" or OS=="win"', {
-      'variables': {
-        'command': [
-          '../../testing/test_env.py',
-          '<(PRODUCT_DIR)/ui_base_unittests<(EXECUTABLE_SUFFIX)',
-          '--brave-new-test-launcher',
-          '--test-launcher-bot-mode',
-          '--asan=<(asan)',
-          '--msan=<(msan)',
-          '--tsan=<(tsan)',
-        ],
-      },
-    }],
     ['OS=="mac" and asan==1 and fastbuild==0', {
       'variables': {
         'files': [