Revert of Move gn _run target generation into test().

third_party/WebKit/Source/web/BUILD.gn

Index: third_party/WebKit/Source/web/BUILD.gn
diff --git a/third_party/WebKit/Source/web/BUILD.gn b/third_party/WebKit/Source/web/BUILD.gn
index f1521450937ec7d2ff5f50b3c66a0811e77e95ab..01134194fd73b6b93d4e65511863c38a17b2e8ff 100644
--- a/third_party/WebKit/Source/web/BUILD.gn
+++ b/third_party/WebKit/Source/web/BUILD.gn
@@ -97,6 +97,15 @@
   }
 }
 
+# TODO(GYP): Delete this after we've converted everything to GN.
+# The _run targets exist only for compatibility w/ GYP.
+group("webkit_unit_tests_run") {
+  testonly = true
+  deps = [
+    ":webkit_unit_tests",
+  ]
+}
+
 group("webkit_unit_tests_data") {
   data = [
     "tests/data/",