[CRD iOS] Implementing save to keychain and user defaults for login info. Refactor remoting service.

remoting/client/ios/app/remoting_settings_view_controller.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.
 
 #if !defined(__has_feature) || !__has_feature(objc_arc)
 #error "This file requires ARC support."
 #endif
 
 #import "remoting/client/ios/app/remoting_settings_view_controller.h"
 
 #import "ios/third_party/material_components_ios/src/components/AppBar/src/MaterialAppBar.h"
 #import "ios/third_party/material_components_ios/src/components/Buttons/src/MaterialButtons.h"
+#import "remoting/client/ios/facade/remoting_service.h"
 
 #include "base/strings/stringprintf.h"
 #include "google_apis/google_api_keys.h"
 #include "net/base/escape.h"
 
 // TODO(nicholss): This should be generated from a remoting/base class:
 
 static NSString* const kReusableIdentifierItem =
     @"remotingSettingsViewControllerItem";
 static UIColor* kBackgroundColor =
@@ skipping 83 matching lines @@
   [self.collectionView registerClass:[MDCCollectionViewTextCell class]
           forCellWithReuseIdentifier:kReusableIdentifierItem];
 
   [self.collectionView registerClass:[MDCCollectionViewTextCell class]
           forSupplementaryViewOfKind:UICollectionElementKindSectionHeader
                  withReuseIdentifier:UICollectionElementKindSectionHeader];
 
   self.styler.cellStyle = MDCCollectionViewCellStyleCard;
 
   _content = [NSMutableArray array];
-  [_content addObject:@[ @"Login" ]];
+  [_content addObject:@[ @"Login", @"Logout" ]];
 }
 
 #pragma mark - UICollectionViewDataSource
 
 - (NSInteger)numberOfSectionsInCollectionView:
     (UICollectionView*)collectionView {
   return (NSInteger)[_content count];
 }
 
 - (NSInteger)collectionView:(UICollectionView*)collectionView
@@ skipping 12 matching lines @@
   if (indexPath.section == 0 && indexPath.item == 0) {
     MDCRaisedButton* accessCodeButton = [[MDCRaisedButton alloc] init];
     [accessCodeButton setTitle:@"Get Access Code"
                       forState:UIControlStateNormal];
     [accessCodeButton sizeToFit];
     [accessCodeButton addTarget:self
                          action:@selector(didTapGetAccessCode:)
                forControlEvents:UIControlEventTouchUpInside];
     accessCodeButton.translatesAutoresizingMaskIntoConstraints = NO;
     cell.accessoryView = accessCodeButton;
-  } else {
-    UISwitch* editingSwitch = [[UISwitch alloc] initWithFrame:CGRectZero];
-    cell.accessoryView = editingSwitch;
+  } else if (indexPath.section == 0 && indexPath.item == 1) {
+    MDCRaisedButton* logoutButton = [[MDCRaisedButton alloc] init];
+    [logoutButton setTitle:@"Logout" forState:UIControlStateNormal];
+    [logoutButton sizeToFit];
+    [logoutButton addTarget:self
+                     action:@selector(didTapLogout:)
+           forControlEvents:UIControlEventTouchUpInside];
+    logoutButton.translatesAutoresizingMaskIntoConstraints = NO;
+    cell.accessoryView = logoutButton;
   }
+
   return cell;
 }
 
 - (UICollectionReusableView*)collectionView:(UICollectionView*)collectionView
           viewForSupplementaryElementOfKind:(NSString*)kind
                                 atIndexPath:(NSIndexPath*)indexPath {
   MDCCollectionViewTextCell* supplementaryView =
       [collectionView dequeueReusableSupplementaryViewOfKind:kind
                                          withReuseIdentifier:kind
                                                 forIndexPath:indexPath];
@@ skipping 22 matching lines @@
   [self dismissViewControllerAnimated:YES completion:nil];
 }
 
 - (void)didTapGetAccessCode:(id)sender {
   NSString* authUri =
       [NSString stringWithCString:GetAuthorizationCodeUri().c_str()
                          encoding:[NSString defaultCStringEncoding]];
   [[UIApplication sharedApplication] openURL:[NSURL URLWithString:authUri]];
 }
 
+- (void)didTapLogout:(id)sender {
+  [[RemotingService SharedInstance] logout];
+}
+
 @end