[ObjC ARC] Converts parts of ios/web/webstate to ARC.

ios/web/web_state/ui/wk_web_view_configuration_provider.mm

Index: ios/web/web_state/ui/wk_web_view_configuration_provider.mm
diff --git a/ios/web/web_state/ui/wk_web_view_configuration_provider.mm b/ios/web/web_state/ui/wk_web_view_configuration_provider.mm
index 2ef20332c7c0c9235a66901cc161996478c6a610..4b1ad99a649a03712598848445aa4e16976fffa5 100644
--- a/ios/web/web_state/ui/wk_web_view_configuration_provider.mm
+++ b/ios/web/web_state/ui/wk_web_view_configuration_provider.mm
@@ -14,6 +14,10 @@
 #import "ios/web/web_state/js/page_script_util.h"
 #import "ios/web/web_state/ui/crw_wk_script_message_router.h"
 
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
 namespace web {
 
 namespace {
@@ -23,10 +27,10 @@ const char kWKWebViewConfigProviderKeyName[] = "wk_web_view_config_provider";
 // Returns an autoreleased instance of WKUserScript to be added to
 // configuration's userContentController.
 WKUserScript* InternalGetEarlyPageScript() {
-  return [[[WKUserScript alloc]
+  return [[WKUserScript alloc]
         initWithSource:GetEarlyPageScript()
          injectionTime:WKUserScriptInjectionTimeAtDocumentStart
-      forMainFrameOnly:YES] autorelease];
+      forMainFrameOnly:YES];
 }
 
 }  // namespace
@@ -57,7 +61,7 @@ WKWebViewConfiguration*
 WKWebViewConfigurationProvider::GetWebViewConfiguration() {
   DCHECK([NSThread isMainThread]);
   if (!configuration_) {
-    configuration_.reset([[WKWebViewConfiguration alloc] init]);
+    configuration_ = [[WKWebViewConfiguration alloc] init];
     if (is_off_the_record_) {
       [configuration_
           setWebsiteDataStore:[WKWebsiteDataStore nonPersistentDataStore]];
@@ -78,7 +82,7 @@ WKWebViewConfigurationProvider::GetWebViewConfiguration() {
         addUserScript:InternalGetEarlyPageScript()];
   }
   // Prevent callers from changing the internals of configuration.
-  return [[configuration_ copy] autorelease];
+  return [configuration_ copy];
 }
 
 CRWWKScriptMessageRouter*
@@ -87,8 +91,8 @@ WKWebViewConfigurationProvider::GetScriptMessageRouter() {
   if (!router_) {
     WKUserContentController* userContentController =
         [GetWebViewConfiguration() userContentController];
-    router_.reset([[CRWWKScriptMessageRouter alloc]
-        initWithUserContentController:userContentController]);
+    router_ = [[CRWWKScriptMessageRouter alloc]
+        initWithUserContentController:userContentController];
   }
   return router_;
 }
@@ -96,12 +100,14 @@ WKWebViewConfigurationProvider::GetScriptMessageRouter() {
 void WKWebViewConfigurationProvider::Purge() {
   DCHECK([NSThread isMainThread]);
 #if !defined(NDEBUG) || !defined(DCHECK_ALWAYS_ON)  // Matches DCHECK_IS_ON.
-  base::WeakNSObject<id> weak_configuration(configuration_);
-  base::WeakNSObject<id> weak_router(router_);
-  base::WeakNSObject<id> weak_process_pool([configuration_ processPool]);
+  __weak id weak_configuration = configuration_;
+  __weak id weak_router = router_;
+  __weak id weak_process_pool = [configuration_ processPool];
+// TODO(crbug.com/522672): Remove this pragma.
+#pragma unused(weak_process_pool)
 #endif  // !defined(NDEBUG) || defined(DCHECK_ALWAYS_ON)
-  configuration_.reset();
-  router_.reset();
+  configuration_ = nil;
+  router_ = nil;
   // Make sure that no one retains configuration, router, processPool.
   DCHECK(!weak_configuration);
   DCHECK(!weak_router);