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

ios/web/BUILD.gn

Index: ios/web/BUILD.gn
diff --git a/ios/web/BUILD.gn b/ios/web/BUILD.gn
index 44d5c17989ee112950cc846ae3971d62adca5ba8..7e7143cc4c1297dd5348f95915f6c44257f1d7da 100644
--- a/ios/web/BUILD.gn
+++ b/ios/web/BUILD.gn
@@ -134,6 +134,21 @@ source_set("web_arc") {
     "public/web_state/crw_web_controller_observer.h",
     "public/web_state/crw_web_user_interface_delegate.h",
     "public/web_state/crw_web_view_proxy.h",
+    "public/web_state/crw_web_view_scroll_view_proxy.h",
+    "public/web_state/global_web_state_observer.h",
+    "public/web_state/js/credential_util.h",
+    "public/web_state/js/crw_js_injection_evaluator.h",
+    "public/web_state/js/crw_js_injection_manager.h",
+    "public/web_state/js/crw_js_injection_receiver.h",
+    "public/web_state/page_display_state.h",
+    "public/web_state/page_display_state.mm",
+    "public/web_state/ui/crw_content_view.h",
+    "public/web_state/ui/crw_generic_content_view.h",
+    "public/web_state/ui/crw_native_content.h",
+    "public/web_state/ui/crw_native_content_provider.h",
+    "public/web_state/ui/crw_web_delegate.h",
+    "public/web_state/ui/crw_web_view_content_view.h",
+    "public/web_state/url_verification_constants.h",
     "string_util.cc",
     "url_scheme_util.mm",
     "url_util.cc",
@@ -199,21 +214,6 @@ source_set("web") {
   ]
 
   sources = [
-    "public/web_state/crw_web_view_scroll_view_proxy.h",
-    "public/web_state/global_web_state_observer.h",
-    "public/web_state/js/credential_util.h",
-    "public/web_state/js/crw_js_injection_evaluator.h",
-    "public/web_state/js/crw_js_injection_manager.h",
-    "public/web_state/js/crw_js_injection_receiver.h",
-    "public/web_state/page_display_state.h",
-    "public/web_state/page_display_state.mm",
-    "public/web_state/ui/crw_content_view.h",
-    "public/web_state/ui/crw_generic_content_view.h",
-    "public/web_state/ui/crw_native_content.h",
-    "public/web_state/ui/crw_native_content_provider.h",
-    "public/web_state/ui/crw_web_delegate.h",
-    "public/web_state/ui/crw_web_view_content_view.h",
-    "public/web_state/url_verification_constants.h",
     "public/web_state/web_state.h",
     "public/web_state/web_state_delegate.h",
     "public/web_state/web_state_delegate_bridge.h",