Add isolate/swarming support for webkit_unit_tests.

Source/web/web_tests.gyp

Index: Source/web/web_tests.gyp
diff --git a/Source/web/web_tests.gyp b/Source/web/web_tests.gyp
index 01e51adbe3a57108f902441586cf7329ee19eff8..87d19c38f8b23551d8a3fac022cd4566b64a13b1 100644
--- a/Source/web/web_tests.gyp
+++ b/Source/web/web_tests.gyp
@@ -174,5 +174,22 @@
                 'includes': [ '../../../../build/apk_test.gypi' ],
             }],
         }],
+        ['test_isolation_mode != "noop"', {
+            'targets': [
+                {
+                    'target_name': 'webkit_unit_tests_run',
+                    'type': 'none',
+                    'dependencies': [
+                        'webkit_unit_tests',
+                    ],
+                    'includes': [
+                        '../../../../build/isolate.gypi',
+                    ],
+                    'sources': [
+                        'webkit_unit_tests.isolate',
+                    ],
+                },
+            ],
+        }],
     ],
 }