Fix iOS GN build after r379128.

url/BUILD.gn

Index: url/BUILD.gn
diff --git a/url/BUILD.gn b/url/BUILD.gn
index 94efa01322b01481fcc42d337e0ade96b0912e0f..828c9ad4e6ad9c98002337024aa3aace10d6ed8f 100644
--- a/url/BUILD.gn
+++ b/url/BUILD.gn
@@ -118,7 +118,6 @@ if (!is_android) {
   test("url_unittests") {
     sources = [
       "gurl_unittest.cc",
-      "mojo/url_gurl_struct_traits_unittest.cc",
       "origin_unittest.cc",
       "run_all_unittests.cc",
       "scheme_host_port_unittest.cc",
@@ -129,6 +128,10 @@ if (!is_android) {
       "url_util_unittest.cc",
     ]
 
+    if (!is_ios) {
+      sources += [ "mojo/url_gurl_struct_traits_unittest.cc" ]
+    }
+
     # TODO(jschuh): crbug.com/167187 fix size_t to int truncations.
     configs += [ "//build/config/compiler:no_size_t_to_int_warning" ]
 
@@ -136,11 +139,16 @@ if (!is_android) {
       ":url",
       "//base",
       "//base/test:test_support",
-      "//mojo/edk/system",
-      "//mojo/edk/test:test_support",
       "//testing/gtest",
       "//third_party/icu:icuuc",
-      "//url/mojo:test_url_mojom_gurl",
     ]
+
+    if (!is_ios) {
+      deps += [
+        "//mojo/edk/system",
+        "//mojo/edk/test:test_support",
+        "//url/mojo:test_url_mojom_gurl",
+      ]
+    }
   }
 }