Revert "[iOS] Dismiss unified consent screen from Recent Tabs."

This reverts commit 55b69ae2.

Reason for revert: Breaking iOS 12 FirstRunTestCase 

Original change's description:
> [iOS] Dismiss unified consent screen from Recent Tabs.
>
> Fixes a bug where the unified consent screen is not dismissed when
> interrupted by a Siri search on the Recent Tabs page.
>
> - Performs complete view controller cleanup on interrupt.
> - Dismisses UnifiedConsentViewController when explicitly required.
> - Does not explicitly release SigninCoordinator in scene controller,
> this is already handled in the completion callback.
>
> Bug: 1115997
> Change-Id: Ib4663fe1136a394020020abc76969761c5e0f170
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2600835
> Reviewed-by: Gauthier Ambard <gambard@chromium.org>
> Commit-Queue: Nohemi Fernandez <fernandex@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#840588}

TBR=gambard@chromium.org,chromium-scoped@luci-project-accounts.iam.gserviceaccount.com,fernandex@chromium.org

Change-Id: I09e836432fc7ce4d6091a3cf3795763c12a91fb5
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 1115997
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2612969Reviewed-by: Gauthier Ambard <gambard@chromium.org>
Commit-Queue: Gauthier Ambard <gambard@chromium.org>
Cr-Commit-Position: refs/heads/master@{#840633}

ios/chrome/browser/ui/authentication/signin/BUILD.gn

@@ -115,7 +115,6 @@ source_set("eg2_tests") {
     "//components/signin/public/base",
     "//ios/chrome/app/strings",
     "//ios/chrome/browser/ui/authentication:eg_test_support+eg2",
-    "//ios/chrome/browser/ui/authentication/unified_consent:constants",
     "//ios/chrome/browser/ui/content_suggestions:feature_flags",
     "//ios/chrome/browser/ui/recent_tabs:recent_tabs_ui_constants",
     "//ios/chrome/browser/ui/settings:constants",

ios/chrome/browser/ui/authentication/signin/signin_coordinator_egtest.mm

@@ -8,7 +8,6 @@
 #import "base/test/ios/wait_util.h"
 #import "ios/chrome/browser/ui/authentication/signin_earl_grey.h"
 #import "ios/chrome/browser/ui/authentication/signin_earl_grey_ui.h"
-#import "ios/chrome/browser/ui/authentication/unified_consent/unified_consent_constants.h"
 #import "ios/chrome/browser/ui/content_suggestions/content_suggestions_feature.h"
 #import "ios/chrome/browser/ui/recent_tabs/recent_tabs_constants.h"
 #include "ios/chrome/grit/ios_strings.h"
@@ -334,29 +333,6 @@ void ChooseImportOrKeepDataSepareteDialog(id<GREYMatcher> choiceButtonMatcher) {
                         tapSettingsLink:NO];
 }
 
-// Tests to dismiss sign-in by opening an URL from another app.
-// Sign-in opened from: recent tabs.
-// Interrupted at: identity selection in user consent.
-- (void)testDismissIdentityPickerSigninFromRecentTabs {
-  FakeChromeIdentity* fakeIdentity = [SigninEarlGrey fakeIdentity1];
-  [SigninEarlGrey addFakeIdentity:fakeIdentity];
-  [self openSigninFromView:OpenSigninMethodFromRecentTabs tapSettingsLink:NO];
-  [[EarlGrey selectElementWithMatcher:grey_accessibilityID(
-                                          kIdentityPickerViewIdentifier)]
-      performAction:grey_tap()];
-
-  // Open the URL as if it was opened from another app.
-  [ChromeEarlGrey simulateExternalAppURLOpening];
-
-  // Check if the URL was opened.
-  const GURL expectedURL("http://www.example.com/");
-  GREYAssertEqual(expectedURL, [ChromeEarlGrey webStateVisibleURL],
-                  @"Didn't open new tab with example.com.");
-
-  // Should be not signed in.
-  [SigninEarlGrey verifySignedOut];
-}
-
 // Tests to dismiss sign-in by opening an URL from another app.
 // Sign-in opened from: recent tabs.
 // Interrupted at: advanced sign-in.

ios/chrome/browser/ui/authentication/signin/user_signin/user_signin_coordinator.mm

@@ -505,10 +505,10 @@ const CGFloat kFadeOutAnimationDuration = 0.16f;
   __weak UserSigninCoordinator* weakSelf = self;
   ProceduralBlock runCompletionCallback = ^{
     [weakSelf
-        viewControllerDismissedWithResult:SigninCoordinatorResultInterrupted
-                                 identity:weakSelf.unifiedConsentCoordinator
-                                              .selectedIdentity
-                    settingsLinkWasTapped:NO];
+        runCompletionCallbackWithSigninResult:SigninCoordinatorResultInterrupted
+                                     identity:self.unifiedConsentCoordinator
+                                                  .selectedIdentity
+                   showAdvancedSettingsSignin:NO];
     if (completion) {
       completion();
     }

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

@@ -52,11 +52,6 @@
   [self.unifiedConsentMediator start];
 }
 
-- (void)stop {
-  [self.unifiedConsentViewController dismissViewControllerAnimated:YES
-                                                        completion:nil];
-}
-
 - (void)scrollToBottom {
   [self.unifiedConsentViewController scrollToBottom];
 }

ios/chrome/browser/ui/main/scene_controller.mm

@@ -807,10 +807,10 @@ const char kMultiWindowOpenInNewWindowHistogram[] =
   }
 
   // The UI should be stopped before the models they observe are stopped.
-  // |self.signinCoordinator| will be released on completion.
   [self.signinCoordinator
       interruptWithAction:SigninCoordinatorInterruptActionNoDismiss
                completion:nil];
+  self.signinCoordinator = nil;
 
   [self.historyCoordinator stop];
   self.historyCoordinator = nil;