[iOS] Using new multiwindow APIs for SSO

Using the new methods from ChromeIdentityServiceImpl:
bool HandleSessionOpenURLContexts(UIScene* scene, NSSet*)
void ApplicationDidDiscardSceneSessions(NSSet*)

 * crrev.com/c/2316308 API declarations
 * crrev.com/i/3182384 Implementing APIs
=> crrev.com/c/2317321 Switching code to use the new APIs

Fixed: 1103833
Change-Id: I97514ea2c05ea3405e83567a5377c4b92673976d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2317321
Commit-Queue: Jérôme Lebel <jlebel@chromium.org>
Reviewed-by: Mark Cogan <marq@chromium.org>
Cr-Commit-Position: refs/heads/master@{#795428}

ios/chrome/app/BUILD.gn

@@ -230,6 +230,7 @@ source_set("app_internal") {
     "//ios/chrome/browser/ui/toolbar:toolbar_ui",
     "//ios/chrome/browser/ui/toolbar/public",
     "//ios/chrome/browser/ui/util",
+    "//ios/chrome/browser/ui/util:ios_multi_window_buildflags",
     "//ios/chrome/browser/ui/util:multiwindow_util",
     "//ios/chrome/browser/ui/webui:webui_internal",
     "//ios/chrome/browser/upgrade",

ios/chrome/app/main_application_delegate.mm

@@ -22,6 +22,7 @@
 #import "ios/chrome/browser/ui/main/scene_controller.h"
 #import "ios/chrome/browser/ui/main/scene_delegate.h"
 #import "ios/chrome/browser/ui/main/scene_state.h"
+#include "ios/chrome/browser/ui/util/multi_window_buildflags.h"
 #include "ios/chrome/browser/ui/util/multi_window_support.h"
 #include "ios/public/provider/chrome/browser/chrome_browser_provider.h"
 #include "ios/public/provider/chrome/browser/signin/chrome_identity_service.h"
@@ -218,6 +219,16 @@
   [_memoryHelper handleMemoryPressure];
 }
 
+#if BUILDFLAG(IOS_MULTIWINDOW_ENABLED)
+- (void)application:(UIApplication*)application
+    didDiscardSceneSessions:(NSSet<UISceneSession*>*)sceneSessions
+    API_AVAILABLE(ios(13)) {
+  ios::GetChromeBrowserProvider()
+      ->GetChromeIdentityService()
+      ->ApplicationDidDiscardSceneSessions(sceneSessions);
+}
+#endif  // BUILDFLAG(IOS_MULTIWINDOW_ENABLED)
+
 #pragma mark - Scenes lifecycle
 
 - (NSInteger)foregroundSceneCount {

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

@@ -2072,11 +2072,11 @@ const char kMultiWindowOpenInNewWindowHistogram[] =
   for (UIOpenURLContext* context : URLContexts) {
     URLOpenerParams* options =
         [[URLOpenerParams alloc] initWithUIOpenURLContext:context];
+    NSSet* URLContextSet = [NSSet setWithObject:context];
     if (!ios::GetChromeBrowserProvider()
              ->GetChromeIdentityService()
-             ->HandleApplicationOpenURL([UIApplication sharedApplication],
-                                        context.URL,
-                                        [options toLaunchOptions])) {
+             ->HandleSessionOpenURLContexts(self.sceneState.scene,
+                                            URLContextSet)) {
       [URLsToOpen addObject:options];
     }
   }