Creates coordinators for displaying alerts

ios/chrome/browser/ui/alert_coordinator/alert_coordinator.mm

Index: ios/chrome/browser/ui/alert_coordinator/alert_coordinator.mm
diff --git a/ios/chrome/browser/ui/alert_coordinator/alert_coordinator.mm b/ios/chrome/browser/ui/alert_coordinator/alert_coordinator.mm
new file mode 100644
index 0000000000000000000000000000000000000000..d507b5e18789a57bf6f165af9c57506553cca818
--- /dev/null
+++ b/ios/chrome/browser/ui/alert_coordinator/alert_coordinator.mm
@@ -0,0 +1,49 @@
+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#import "ios/chrome/browser/ui/alert_coordinator/alert_coordinator.h"
+
+#import "base/mac/scoped_nsobject.h"
+#include "ui/base/l10n/l10n_util.h"
+#include "ui/strings/grit/ui_strings.h"
+
+@interface AlertCoordinator () {
+  // Stores the title of the alert.
+  base::scoped_nsobject<NSString> _title;
+}
+
+@end
+
+@implementation AlertCoordinator
+
+- (instancetype)initWithViewController:(UIViewController*)viewController
+                                 title:(NSString*)title {
+  self = [super initWithBaseViewController:viewController];
+  if (self) {
+    _title.reset([title copy]);
+  }
+  return self;
+}
+
+#pragma mark - Private Methods
+
+- (BOOL)shouldStart {
+  if ([self actionCount] == 0) {
+    [self addItemWithTitle:l10n_util::GetNSString(IDS_APP_OK)
+                    action:^{
+                    }

[lpromero, 2016/07/06 09:03:59]

Pass nil as action block, and accept nil in the API.

[gambard, 2016/07/07 08:57:43]

Done.

+               destructive:NO];
+  }
+  return YES;
+}
+
+- (UIAlertController*)createAlertController {
+  UIAlertController* alert =
+      [UIAlertController alertControllerWithTitle:_title
+                                          message:self.message
+                                   preferredStyle:UIAlertControllerStyleAlert];
+  return alert;

[lpromero, 2016/07/06 09:03:59]

If renamed newAlertController, you need to return [alert retain].

[gambard, 2016/07/07 08:57:43]

Acknowledged.

+}
+
+@end