[ObjC ARC] Converts ios/chrome/app/safe_mode:safe_mode to ARC.

ios/chrome/app/safe_mode/safe_mode_coordinator.mm

Index: ios/chrome/app/safe_mode/safe_mode_coordinator.mm
diff --git a/ios/chrome/app/safe_mode/safe_mode_coordinator.mm b/ios/chrome/app/safe_mode/safe_mode_coordinator.mm
index a91978506315961044ee12447ef3e2dcae1980bc..c5f8b867be5cf1b7e8e7adeac5147391e8ae144f 100644
--- a/ios/chrome/app/safe_mode/safe_mode_coordinator.mm
+++ b/ios/chrome/app/safe_mode/safe_mode_coordinator.mm
@@ -4,34 +4,26 @@
 
 #import "ios/chrome/app/safe_mode/safe_mode_coordinator.h"
 
-#include "base/mac/scoped_nsobject.h"
+#import "base/logging.h"
 #import "ios/chrome/app/safe_mode/safe_mode_view_controller.h"
 #include "ios/chrome/browser/crash_loop_detection_util.h"
 
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
 namespace {
 const int kStartupCrashLoopThreshold = 2;
 }
 
-@interface SafeModeCoordinator ()<SafeModeViewControllerDelegate> {
-  // Weak pointer to window passed on init.
-  base::WeakNSObject<UIWindow> _window;
-  // Weak pointer backing property of the same name.
-  base::WeakNSProtocol<id<SafeModeCoordinatorDelegate>> _delegate;
-}
-
+@interface SafeModeCoordinator ()<SafeModeViewControllerDelegate>
 @end
 
-@implementation SafeModeCoordinator
-
-#pragma mark - property implementation.
-
-- (id<SafeModeCoordinatorDelegate>)delegate {
-  return _delegate;
+@implementation SafeModeCoordinator {
+  __weak UIWindow* _window;
 }
 
-- (void)setDelegate:(id<SafeModeCoordinatorDelegate>)delegate {
-  _delegate.reset(delegate);
-}
+@synthesize delegate = _delegate;
 
 #pragma mark - Public class methods
 
@@ -54,8 +46,8 @@ const int kStartupCrashLoopThreshold = 2;
   // General note: Safe mode should be safe; it should not depend on other
   // objects being created. Be extremely conservative when adding code to this
   // method.
-  base::scoped_nsobject<SafeModeViewController> viewController(
-      [[SafeModeViewController alloc] initWithDelegate:self]);
+  SafeModeViewController* viewController =
+      [[SafeModeViewController alloc] initWithDelegate:self];
   [self.window setRootViewController:viewController];
 
   // Reset the crash count; the user may change something based on the recovery