[ios] Expands InfobarContainerCoordinator unittests.

- Adds a stop method to InfobarCoordinator that needs to be called by
its subclasses. This nils the animatedFullscreenDisabler_ which prevents
crashes while testing when trying to access it when BrowserState has been
dealloced.

- Adds more test cases to InfobarContainerCoordinatorUnitTests

Bug: 961343
Change-Id: I9957968de7fe4f00f9e951c49bd39d885989ae62
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1703460
Commit-Queue: Sergio Collazos <sczs@chromium.org>
Reviewed-by: Chris Lu <thegreenfrog@chromium.org>
Reviewed-by: Peter Lee <pkl@chromium.org>
Cr-Commit-Position: refs/heads/master@{#678519}

ios/chrome/browser/ui/infobars/coordinators/infobar_confirm_coordinator.mm

@@ -61,6 +61,7 @@
 }
 
 - (void)stop {
+  [super stop];
   if (self.started) {
     self.started = NO;
     // RemoveInfoBar() will delete the InfobarIOS that owns this Coordinator

ios/chrome/browser/ui/infobars/coordinators/infobar_coordinator.h

@@ -65,6 +65,9 @@ enum class InfobarBannerPresentationState;
 - (void)dismissInfobarBannerAnimated:(BOOL)animated
                           completion:(void (^)())completion;
 
+// Stops this Coordinator.
+- (void)stop NS_REQUIRES_SUPER;
+
 // YES if the Coordinator has been started.
 @property(nonatomic, assign) BOOL started;
 

ios/chrome/browser/ui/infobars/coordinators/infobar_coordinator.mm

@@ -81,6 +81,11 @@ const CGFloat kiPadBannerOverlapWithOmnibox = 10.0;
 
 #pragma mark - Public Methods.
 
+- (void)stop {
+  animatedFullscreenDisabler_ = nullptr;
+  _infobarDelegate = nil;
+}
+
 - (void)presentInfobarBannerAnimated:(BOOL)animated
                           completion:(ProceduralBlock)completion {
   DCHECK(self.browserState);

ios/chrome/browser/ui/infobars/coordinators/infobar_password_coordinator.mm

@@ -90,6 +90,7 @@
 }
 
 - (void)stop {
+  [super stop];
   if (self.started) {
     self.started = NO;
     // RemoveInfoBar() will delete the InfobarIOS that owns this Coordinator