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

content/content_unittests.isolate

Index: content/content_unittests.isolate
diff --git a/content/content_unittests.isolate b/content/content_unittests.isolate
index 502e225e1d31f3ed290009b8f7c0384e9c795894..3ddb135cf70220aef0c98f277085395c3e4529f8 100644
--- a/content/content_unittests.isolate
+++ b/content/content_unittests.isolate
@@ -34,7 +34,21 @@
         ],
       },
     }],
-    ['OS=="linux"', {
+    ['use_x11==0', {
+      'variables': {
+        'command': [
+          '../testing/test_env.py',
+          '<(PRODUCT_DIR)/content_unittests<(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',
@@ -49,30 +63,20 @@
         ],
         'files': [
           '../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',
         ],
       },
     }],
     ['OS=="mac"', {
       'variables': {
-        'command': [
-          '../testing/test_env.py',
-          '<(PRODUCT_DIR)/content_unittests<(EXECUTABLE_SUFFIX)',
-          '--brave-new-test-launcher',
-          '--test-launcher-bot-mode',
-          '--asan=<(asan)',
-          '--lsan=<(lsan)',
-          '--msan=<(msan)',
-          '--tsan=<(tsan)',
-        ],
         'files': [
           '<(PRODUCT_DIR)/ffmpegsumo.so',
           '<(PRODUCT_DIR)/osmesa.so',
@@ -81,16 +85,6 @@
     }],
     ['OS=="win"', {
       'variables': {
-        'command': [
-          '../testing/test_env.py',
-          '<(PRODUCT_DIR)/content_unittests<(EXECUTABLE_SUFFIX)',
-          '--brave-new-test-launcher',
-          '--test-launcher-bot-mode',
-          '--asan=<(asan)',
-          '--lsan=<(lsan)',
-          '--msan=<(msan)',
-          '--tsan=<(tsan)',
-        ],
         'files': [
           '<(PRODUCT_DIR)/ffmpegsumo.dll',
           '<(PRODUCT_DIR)/osmesa.dll',