[ARC] Converts part of ios/web to ARC.

ios/web/BUILD.gn

Index: ios/web/BUILD.gn
diff --git a/ios/web/BUILD.gn b/ios/web/BUILD.gn
index 4011076470a02127a656475a821b40b7419d369c..fd75f7af15f144f87a9c4222602da2ccb6fa7242 100644
--- a/ios/web/BUILD.gn
+++ b/ios/web/BUILD.gn
@@ -191,6 +191,16 @@ source_set("web_arc") {
     "web_state/js/crw_js_plugin_placeholder_manager.mm",
     "web_state/js/crw_js_post_request_loader.h",
     "web_state/js/crw_js_post_request_loader.mm",
+    "web_state/js/crw_js_window_id_manager.h",
+    "web_state/js/crw_js_window_id_manager.mm",
+    "web_state/js/page_script_util.h",
+    "web_state/js/page_script_util.mm",
+    "web_state/page_viewport_state.h",
+    "web_state/page_viewport_state.mm",
+    "web_state/ui/crw_generic_content_view.mm",
+    "web_state/ui/crw_swipe_recognizer_provider.h",
+    "web_state/ui/crw_touch_tracking_recognizer.h",
+    "web_state/ui/crw_touch_tracking_recognizer.mm",
     "web_thread_impl.cc",
     "web_thread_impl.h",
     "web_view_creation_util.mm",
@@ -252,16 +262,6 @@ source_set("web") {
   ]
 
   sources = [
-    "web_state/js/crw_js_window_id_manager.h",
-    "web_state/js/crw_js_window_id_manager.mm",
-    "web_state/js/page_script_util.h",
-    "web_state/js/page_script_util.mm",
-    "web_state/page_viewport_state.h",
-    "web_state/page_viewport_state.mm",
-    "web_state/ui/crw_generic_content_view.mm",
-    "web_state/ui/crw_swipe_recognizer_provider.h",
-    "web_state/ui/crw_touch_tracking_recognizer.h",
-    "web_state/ui/crw_touch_tracking_recognizer.mm",
     "web_state/ui/crw_web_controller.h",
     "web_state/ui/crw_web_controller.mm",
     "web_state/ui/crw_web_controller_container_view.h",