Migrate both normal and incognito sessions to multi-window.

The flag for the previous window was reset too early before the
incognito session was restored, and that caused the problem of
not migrating incognito sessions


Bug: 1139894
Change-Id: I40384b3f2051a79f18cdd0fc755cc01b402cdd2a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2499177
Commit-Queue: Mohammad Refaat <mrefaat@chromium.org>
Reviewed-by: Olivier Robin <olivierrobin@chromium.org>
Reviewed-by: Mark Cogan <marq@chromium.org>
Cr-Commit-Position: refs/heads/master@{#821397}

components/previous_session_info/previous_session_info.h

@@ -101,7 +101,9 @@ enum class DeviceBatteryState {
 @property(nonatomic, assign, readonly) BOOL OSRestartedAfterPreviousSession;
 
 // Whether the previous session was on Multi Window enabled version of the
-// application.
+// application. A previous session doesn't have to be from a previous run, in
+// the case of single window to multiple windows migration, after the first
+// session created/restored the flag value should be updated to |YES|.
 // TODO(crbug.com/1109280): Remove after the migration to Multi-Window sessions
 // is done.
 @property(nonatomic, assign, readonly) BOOL isMultiWindowEnabledSession;
@@ -175,6 +177,11 @@ enum class DeviceBatteryState {
 // Empties the list of connected session.
 - (void)resetConnectedSceneSessionIDs;
 
+// Updates the local and the saved Multi Window support status.
+// TODO(crbug.com/1109280): Remove after the migration to Multi-Window
+// sessions is done.
+- (void)updateMultiWindowSupportStatus;
+
 // Must be called when Chrome starts session restoration. The returned closure
 // runner will clear up the flag when destroyed. Can be used on different
 // threads.

components/previous_session_info/previous_session_info.mm

@@ -259,12 +259,6 @@ static PreviousSessionInfo* gSharedInstance = nil;
   NSString* currentLanguage = [[NSLocale preferredLanguages] objectAtIndex:0];
   [defaults setObject:currentLanguage forKey:kLastRanLanguage];
 
-  // Set the current Multi-Window support state.
-  // TODO(crbug.com/1109280): Remove after the migration to Multi-Window
-  // sessions is done.
-  [defaults setBool:base::ios::IsMultiwindowSupported()
-             forKey:kPreviousSessionInfoMultiWindowEnabled];
-
   // Clear the memory warning flag.
   [defaults
       removeObjectForKey:previous_session_info_constants::
@@ -494,6 +488,15 @@ static PreviousSessionInfo* gSharedInstance = nil;
   [self synchronizeSceneSessionIDs];
 }
 
+- (void)updateMultiWindowSupportStatus {
+  gSharedInstance.isMultiWindowEnabledSession =
+      base::ios::IsMultiwindowSupported();
+  NSUserDefaults* defaults = [NSUserDefaults standardUserDefaults];
+  [defaults setBool:gSharedInstance.isMultiWindowEnabledSession
+             forKey:kPreviousSessionInfoMultiWindowEnabled];
+  [defaults synchronize];
+}
+
 - (base::ScopedClosureRunner)startSessionRestoration {
   if (self.numberOfSessionsBeingRestored == 0) {
     [NSUserDefaults.standardUserDefaults
@@ -509,12 +512,6 @@ static PreviousSessionInfo* gSharedInstance = nil;
     --self.numberOfSessionsBeingRestored;
     if (self.numberOfSessionsBeingRestored == 0) {
       [self resetSessionRestorationFlag];
-      // Once the first patch of sessions is restored. Update the Multi-Window
-      // flag so it's not used again in the same run.
-      // TODO(crbug.com/1109280): Remove after the migration to Multi-Window
-      // sessions is done.
-      gSharedInstance.isMultiWindowEnabledSession =
-          base::ios::IsMultiwindowSupported();
     }
   }));
 }

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

@@ -645,6 +645,14 @@ const char kMultiWindowOpenInNewWindowHistogram[] =
   [self createInitialUI:(startInIncognito ? ApplicationMode::INCOGNITO
                                           : ApplicationMode::NORMAL)];
 
+  // By reaching here, it's guaranteed that both Normal and incognito sessions
+  // were restored. and if it's the first time that multi-window sessions are
+  // created, the migration was done. Update the Multi-Window flag so it's not
+  // used again in the same run when creating new windows.
+  // TODO(crbug.com/1109280): Remove after the migration to Multi-Window
+  // sessions is done.
+  [[PreviousSessionInfo sharedInstance] updateMultiWindowSupportStatus];
+
   if ([self shouldShowRestorePrompt]) {
     [self.sceneState.appState.startupInformation
             .restoreHelper showRestorePrompt];