[iOS] Implementation of "Not johndoe@example.com" in the sign-in promo

When the user clicks on	"Not johndoe@example.com", the sign-in dialog is
opened with the identity chooser dialog opened.

Bug: 827072
Cq-Include-Trybots: luci.chromium.try:ios-simulator-full-configs;master.tryserver.chromium.mac:ios-simulator-cronet
Change-Id: Ic7aff360ee229ebd83063dfbef5b9bc7fe36d345
Reviewed-on: https://chromium-review.googlesource.com/1186739
Commit-Queue: Jérôme Lebel <jlebel@chromium.org>
Reviewed-by: Gauthier Ambard <gambard@chromium.org>
Cr-Commit-Position: refs/heads/master@{#585820}

ios/chrome/browser/ui/authentication/unified_consent/unified_consent_coordinator.mm

@@ -18,12 +18,19 @@
 @interface UnifiedConsentCoordinator ()<IdentityChooserCoordinatorDelegate,
                                         UnifiedConsentViewControllerDelegate>
 
+// Unified consent mediator.
 @property(nonatomic, strong) UnifiedConsentMediator* unifiedConsentMediator;
-@property(nonatomic, strong, readwrite)
+// Unified consent view controller.
+@property(nonatomic, strong)
     UnifiedConsentViewController* unifiedConsentViewController;
-@property(nonatomic, readwrite) BOOL settingsLinkWasTapped;
+// YES if the user tapped on the setting link.
+@property(nonatomic, assign) BOOL settingsLinkWasTapped;
+// Identity chooser coordinator.
 @property(nonatomic, strong)
     IdentityChooserCoordinator* identityChooserCoordinator;
+// YES if no default identity as been set before starting the coordinator.
+@property(nonatomic, assign) BOOL shouldOpenIdentityChooserDialogWhenAppearing;
+
 @end
 
 @implementation UnifiedConsentCoordinator
@@ -34,6 +41,8 @@
 @synthesize settingsLinkWasTapped = _settingsLinkWasTapped;
 @synthesize interactable = _interactable;
 @synthesize identityChooserCoordinator = _identityChooserCoordinator;
+@synthesize shouldOpenIdentityChooserDialogWhenAppearing =
+    _shouldOpenIdentityChooserDialogWhenAppearing;
 
 - (instancetype)init {
   self = [super init];
@@ -48,6 +57,11 @@
 
 - (void)start {
   self.unifiedConsentViewController.interactable = self.interactable;
+  // If no selected identity has been set, the identity chooser dialog needs
+  // to be opened when the view will appear. This test has to be done before
+  // to start the mediator since it will select a default one on start.
+  self.shouldOpenIdentityChooserDialogWhenAppearing =
+      !self.unifiedConsentMediator.selectedIdentity;
   [self.unifiedConsentMediator start];
 }
 
@@ -79,8 +93,30 @@
   return self.unifiedConsentViewController.isScrolledToBottom;
 }
 
+#pragma mark - Private
+
+// Opens the identity chooser dialog with an animation from |point|.
+- (void)showIdentityChooserDialogWithPoint:(CGPoint)point {
+  self.identityChooserCoordinator = [[IdentityChooserCoordinator alloc]
+      initWithBaseViewController:self.unifiedConsentViewController];
+  self.identityChooserCoordinator.delegate = self;
+  self.identityChooserCoordinator.origin = point;
+  [self.identityChooserCoordinator start];
+  self.identityChooserCoordinator.selectedIdentity = self.selectedIdentity;
+}
+
 #pragma mark - UnifiedConsentViewControllerDelegate
 
+- (void)unifiedConsentViewControllerViewDidAppear:
+    (UnifiedConsentViewController*)controller {
+  if (!self.shouldOpenIdentityChooserDialogWhenAppearing)
+    return;
+  CGFloat midX = CGRectGetMidX(self.unifiedConsentViewController.view.bounds);
+  CGFloat midY = CGRectGetMidY(self.unifiedConsentViewController.view.bounds);
+  CGPoint point = CGPointMake(midX, midY);
+  [self showIdentityChooserDialogWithPoint:point];
+}
+
 - (void)unifiedConsentViewControllerDidTapSettingsLink:
     (UnifiedConsentViewController*)controller {
   DCHECK_EQ(self.unifiedConsentViewController, controller);
@@ -93,12 +129,7 @@
             (UnifiedConsentViewController*)controller
                                                      atPoint:(CGPoint)point {
   DCHECK_EQ(self.unifiedConsentViewController, controller);
-  self.identityChooserCoordinator = [[IdentityChooserCoordinator alloc]
-      initWithBaseViewController:self.unifiedConsentViewController];
-  self.identityChooserCoordinator.delegate = self;
-  self.identityChooserCoordinator.origin = point;
-  [self.identityChooserCoordinator start];
-  self.identityChooserCoordinator.selectedIdentity = self.selectedIdentity;
+  [self showIdentityChooserDialogWithPoint:point];
 }
 
 - (void)unifiedConsentViewControllerDidReachBottom:

ios/chrome/browser/ui/authentication/unified_consent/unified_consent_mediator.mm

@@ -20,9 +20,13 @@
   std::unique_ptr<ChromeBrowserProviderObserverBridge> _browserProviderObserver;
 }
 
+// Unified consent view controller.
 @property(nonatomic, weak)
     UnifiedConsentViewController* unifiedConsentViewController;
+// Image for the selected identity avatar.
 @property(nonatomic, strong) UIImage* selectedIdentityAvatar;
+// NO until the mediator is started.
+@property(nonatomic, assign) BOOL started;
 
 @end
 
@@ -31,6 +35,7 @@
 @synthesize selectedIdentityAvatar = _selectedIdentityAvatar;
 @synthesize selectedIdentity = _selectedIdentity;
 @synthesize unifiedConsentViewController = _unifiedConsentViewController;
+@synthesize started = _started;
 
 - (instancetype)initWithUnifiedConsentViewController:
     (UnifiedConsentViewController*)viewController {
@@ -41,12 +46,6 @@
         std::make_unique<ChromeIdentityServiceObserverBridge>(self);
     _browserProviderObserver =
         std::make_unique<ChromeBrowserProviderObserverBridge>(self);
-    NSArray* identities = ios::GetChromeBrowserProvider()
-                              ->GetChromeIdentityService()
-                              ->GetAllIdentitiesSortedForDisplay();
-    if (identities.count != 0) {
-      _selectedIdentity = identities[0];
-    }
   }
   return self;
 }
@@ -65,14 +64,25 @@
 }
 
 - (void)start {
+  NSArray* identities = ios::GetChromeBrowserProvider()
+                            ->GetChromeIdentityService()
+                            ->GetAllIdentitiesSortedForDisplay();
+  if (identities.count != 0) {
+    self.selectedIdentity = identities[0];
+  }
   // Make sure the view is loaded so the mediator can set it up.
   [self.unifiedConsentViewController loadViewIfNeeded];
+  self.started = YES;
   [self updateViewController];
 }
 
 #pragma mark - Private
 
+// Updates the view if the mediator has been started.
 - (void)updateViewController {
+  // The UI should not be updated before the view is loaded.
+  if (!self.started)
+    return;
   if (self.selectedIdentity) {
     [self.unifiedConsentViewController
         updateIdentityPickerViewWithUserFullName:self.selectedIdentity

ios/chrome/browser/ui/authentication/unified_consent/unified_consent_view_controller.mm

@@ -325,6 +325,10 @@ NSString* const kSyncCompleteIconName = @"ic_sync_complete";
   [self updateScrollViewAndImageBackgroundView];
 }
 
+- (void)viewDidAppear:(BOOL)animated {
+  [self.delegate unifiedConsentViewControllerViewDidAppear:self];
+}
+
 // Updates the scroll view content inset, used by pre iOS 11.
 - (void)viewWillTransitionToSize:(CGSize)size
        withTransitionCoordinator:

ios/chrome/browser/ui/authentication/unified_consent/unified_consent_view_controller_delegate.h

@@ -27,6 +27,10 @@
 - (void)unifiedConsentViewControllerDidReachBottom:
     (UnifiedConsentViewController*)controller;
 
+// Called when the view appears.
+- (void)unifiedConsentViewControllerViewDidAppear:
+    (UnifiedConsentViewController*)controller;
+
 @end
 
 #endif  // IOS_CHROME_BROWSER_UI_AUTHENTICATION_UNIFIED_CONSENT_UNIFIED_CONSENT_VIEW_CONTROLLER_DELEGATE_H_