[iOS][coordinator] Modernize Identity Chooser Coordinator.

This CL modernizes the IdentityChooserCoordinator to use |browser| in
the initializer.

Bug: 1029346, 1048410

Change-Id: I6b5440e2124c9d62060bc6eba70446c7fcb1ae5b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2078476Reviewed-by: Mark Cogan <marq@chromium.org>
Commit-Queue: Nazerke Kalidolda <nazerke@google.com>
Cr-Commit-Position: refs/heads/master@{#745438}

ios/chrome/browser/ui/authentication/unified_consent/identity_chooser/identity_chooser_coordinator.h

@@ -15,6 +15,14 @@
 // Coordinator to display the identity chooser view controller.
 @interface IdentityChooserCoordinator : ChromeCoordinator
 
+// Unavailable, use -initWithBaseViewController:browser:.
+- (instancetype)initWithBaseViewController:(UIViewController*)viewController
+    NS_UNAVAILABLE;
+// Unavailable, use -initWithBaseViewController:browser:.
+- (instancetype)initWithBaseViewController:(UIViewController*)viewController
+                              browserState:(ChromeBrowserState*)browserState
+    NS_UNAVAILABLE;
+
 // Selected ChromeIdentity.
 @property(nonatomic, strong) ChromeIdentity* selectedIdentity;
 // Delegate.

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

@@ -91,7 +91,8 @@
 // Opens the identity chooser dialog with an animation from |point|.
 - (void)showIdentityChooserDialogWithPoint:(CGPoint)point {
   self.identityChooserCoordinator = [[IdentityChooserCoordinator alloc]
-      initWithBaseViewController:self.unifiedConsentViewController];
+      initWithBaseViewController:self.unifiedConsentViewController
+                         browser:self.browser];
   self.identityChooserCoordinator.delegate = self;
   self.identityChooserCoordinator.origin = point;
   [self.identityChooserCoordinator start];