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

chrome/unit_tests.isolate

Index: chrome/unit_tests.isolate
diff --git a/chrome/unit_tests.isolate b/chrome/unit_tests.isolate
index bee477c64bee73f81306651711d6b8f179d0f662..638ef6d6e39d3f21b30acdce98b9d9bfe39e76c4 100644
--- a/chrome/unit_tests.isolate
+++ b/chrome/unit_tests.isolate
@@ -39,7 +39,21 @@
         ],
       },
     }],
-    ['OS=="linux"', {
+    ['use_x11==0', {
+      'variables': {
+        'command': [
+          '../testing/test_env.py',
+          '<(PRODUCT_DIR)/unit_tests<(EXECUTABLE_SUFFIX)',
+          '--brave-new-test-launcher',
+          '--test-launcher-bot-mode',
+          '--asan=<(asan)',
+          '--lsan=<(lsan)',
+          '--msan=<(msan)',
+          '--tsan=<(tsan)',
+        ],
+      },
+    }],
+    ['use_x11==1', {
       'variables': {
         'command': [
           '../testing/xvfb.py',
@@ -54,16 +68,16 @@
         ],
         'files': [
           '../testing/xvfb.py',
-          '<(PRODUCT_DIR)/libffmpegsumo.so',
-          '<(PRODUCT_DIR)/libosmesa.so',
-          '<(PRODUCT_DIR)/locales/fr.pak',
+          '<(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',
+          '<(PRODUCT_DIR)/locales/fr.pak',
         ],
       },
     }],
@@ -106,20 +120,6 @@
         ],
       },
     }],
-    ['OS=="mac" or OS=="win"', {
-      'variables': {
-        'command': [
-          '../testing/test_env.py',
-          '<(PRODUCT_DIR)/unit_tests<(EXECUTABLE_SUFFIX)',
-          '--brave-new-test-launcher',
-          '--test-launcher-bot-mode',
-          '--asan=<(asan)',
-          '--lsan=<(lsan)',
-          '--msan=<(msan)',
-          '--tsan=<(tsan)',
-        ],
-      },
-    }],
     ['OS=="win"', {
       'variables': {
         'files': [