[ObjC ARC] Converts ios/web:ios_web_general_unittests to ARC.

Automatically generated ARCMigrate commit
Notable issues:None
BUG=624363
TEST=None

Review-Url: https://codereview.chromium.org/2934083002
Cr-Commit-Position: refs/heads/master@{#479334}

ios/web/BUILD.gn

@@ -469,6 +469,7 @@ test("ios_web_unittests") {
 }
 
 source_set("ios_web_general_unittests") {
+  configs += [ "//build/config/compiler:enable_arc" ]
   testonly = true
   deps = [
     ":core",

ios/web/active_state_manager_impl_unittest.mm

@@ -13,6 +13,10 @@
 #include "testing/gtest/include/gtest/gtest.h"
 #include "testing/platform_test.h"
 
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
 namespace web {
 namespace {
 

ios/web/history_state_util_unittest.mm

@@ -11,6 +11,10 @@
 #import "testing/gtest_mac.h"
 #include "url/gurl.h"
 
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
 namespace web {
 namespace {
 struct TestEntry {

ios/web/test/web_test_unittest.mm

@@ -9,6 +9,10 @@
 #import "ios/web/test/wk_web_view_crash_utils.h"
 #include "testing/gtest/include/gtest/gtest-spi.h"
 
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
 namespace {
 
 // Fixture to test that the WebTest fixture properly fails tests when the render
@@ -17,15 +21,15 @@
  protected:
   void SetUp() override {
     web::WebTestWithWebController::SetUp();
-    web_view_.reset([web::BuildTerminatedWKWebView() retain]);
-    base::scoped_nsobject<TestWebViewContentView> web_view_content_view(
+    web_view_ = web::BuildTerminatedWKWebView();
+    TestWebViewContentView* web_view_content_view =
         [[TestWebViewContentView alloc]
             initWithMockWebView:web_view_
-                     scrollView:[web_view_ scrollView]]);
+                     scrollView:[web_view_ scrollView]];
     [web_controller() injectWebViewContentView:web_view_content_view];
   }
 
-  base::scoped_nsobject<WKWebView> web_view_;
+  WKWebView* web_view_;
 };
 
 // Tests that the WebTest fixture triggers a test failure when a render process

ios/web/url_scheme_util_unittest.mm

@@ -9,6 +9,10 @@
 #import "testing/gtest_mac.h"
 #include "url/gurl.h"
 
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
 namespace web {
 
 TEST(URLSchemeUtilTest, UrlHasWebScheme) {