Adding mediator for Sign-in promo

ios/chrome/browser/ui/authentication/signin_promo_view_mediator.mm

+// Copyright 2017 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/authentication/signin_promo_view_mediator.h"
+
+#include "base/strings/sys_string_conversions.h"
+#include "ios/chrome/grit/ios_chromium_strings.h"
+#include "ios/chrome/grit/ios_strings.h"
+#import "ios/public/provider/chrome/browser/chrome_browser_provider.h"
+#import "ios/public/provider/chrome/browser/signin/signin_resources_provider.h"
+#import "ios/third_party/material_components_ios/src/components/Buttons/src/MaterialButtons.h"
+#include "ui/base/l10n/l10n_util.h"
+
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
+@implementation SigninPromoViewMediator
+
+@synthesize userFullName = _userFullName;
+@synthesize userEmail = _userEmail;
+@synthesize userImage = _userImage;
+
+#pragma mark - SigninPromoViewConfigurator
+
+- (void)configureSigninPromoView:(SigninPromoView*)signinPromoView {
+  if (!_userEmail) {
+    DCHECK(!_userFullName);
+    DCHECK(!_userImage);
+    signinPromoView.mode = SigninPromoViewColdStateMode;
+    [signinPromoView.primaryButton

[msarda, 2017/03/27 09:34:17]

From our conversation, I understood the following:
* the SigninPromoView will have a cold state and a warm state
* the cold state will be entirely configured by the view
* the warm state will be configured by the mediator
Is this correct?

If my understanding is correct, then the mediator should not set the primary
button title.

[jlebel, 2017/03/27 21:34:43]

Done.

+        setTitle:l10n_util::GetNSString(
+                     IDS_IOS_OPTIONS_IMPORT_DATA_TITLE_SIGNIN)
+        forState:UIControlStateNormal];
+  } else {
+    signinPromoView.mode = SigninPromoViewWarmStateMode;
+    [signinPromoView.primaryButton
+        setTitle:l10n_util::GetNSStringF(
+                     IDS_IOS_SIGNIN_PROMO_CONTINUE_AS,
+                     base::SysNSStringToUTF16(_userFullName))
+        forState:UIControlStateNormal];
+    [signinPromoView.secondaryButton
+        setTitle:l10n_util::GetNSStringF(IDS_IOS_SIGNIN_PROMO_NOT,
+                                         base::SysNSStringToUTF16(_userEmail))
+        forState:UIControlStateNormal];

[msarda, 2017/03/27 09:34:16]

Optional nit:
UIImage* image = _userImage;
if (!image) {
  image =
ios::GetChromeBrowserProvider()->->GetSigninResourcesProvider()->GetDefaultAvatar();
}
[signinPromoView setProfileImage:image];

[jlebel, 2017/03/27 21:34:43]

Done.

+    if (_userImage) {
+      [signinPromoView setProfileImage:_userImage];
+    } else {
+      [signinPromoView setProfileImage:ios::GetChromeBrowserProvider()
+                                           ->GetSigninResourcesProvider()
+                                           ->GetDefaultAvatar()];
+    }
+  }
+}
+
+@end