Persist Interaction State for tabs (#3824)

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Task/Issue URL: https://app.asana.com/0/0/1208991633646641/f
Tech Design URL:
https://app.asana.com/0/481882893211075/1208983861756006/f
CC:

**Description**:

Adds storage and automatically stores WKWebView's interaction state data
for each tab. These are used to restore back/forward history and scroll
position on next launch after app was terminated.

**Steps to test this PR**:
1. Mark yourself as internal user to enable the feature. Restart is
required for the flag to have an effect.
1. Open a few tabs, navigate to various links so that navigating
back/forward is possible. Scroll can be adjusted.
2. Terminate the app. 
3. Verify last opened tab is visible and website is scrolled to
(roughly) the same position on the screen.
4. Verify navigation history is available and working properly.
5. Use Fire button. Verify all cache files are being removed. You can
check the directory by putting a breakpoint somewhere in
`TabInteractionStateDiskSource` and printing
`interactionStateCacheLocation` or use debug menu to see the list of
cache files.
6. Open a few tabs again, enable Automatic Data Clearing.
7. Verify all interaction cache files are removed.

<!--
Before submitting a PR, please ensure you have tested the combinations
you expect the reviewer to test, then delete configurations you *know*
do not need explicit testing.

Using a simulator where a physical device is unavailable is acceptable.
-->

**Definition of Done (Internal Only)**:

* [ ] Does this PR satisfy our [Definition of
Done](https://app.asana.com/0/1202500774821704/1207634633537039/f)?

---
###### Internal references:
[Software Engineering
Expectations](https://app.asana.com/0/59792373528535/199064865822552)
[Technical Design
Template](https://app.asana.com/0/59792373528535/184709971311943)

Core/FeatureFlag.swift

@@ -63,6 +63,9 @@ public enum FeatureFlag: String {
 
     /// https://app.asana.com/0/0/1208767141940869/f
     case privacyProFreeTrialJan25
+
+    /// https://app.asana.com/0/1206226850447395/1206307878076518
+    case webViewStateRestoration
 }
 
 extension FeatureFlag: FeatureFlagDescribing {
@@ -146,6 +149,8 @@ extension FeatureFlag: FeatureFlagDescribing {
             return .remoteReleasable(.subfeature(AIChatSubfeature.deepLink))
         case .tabManagerMultiSelection:
             return .internalOnly()
+        case .webViewStateRestoration:
+            return .internalOnly()
         }
     }
 }

Core/PixelEvent.swift

@@ -960,6 +960,12 @@ extension Pixel {
         // MARK: Lifecycle
         case appDidTransitionToUnexpectedState
 
+        // MARK: Tab interaction state debug pixels
+        case tabInteractionStateSourceMissingRootDirectory
+        case tabInteractionStateSourceFailedToWrite
+
+        case tabInteractionStateFailedToRestore
+        case tabInteractionStateRestorationTime(_ time: BucketAggregation)
     }
 
 }
@@ -1560,8 +1566,20 @@ extension Pixel.Event {
         case .debugWebsiteDataStoresNotClearedOne: return "m_d_wkwebsitedatastoresnotcleared_one"
         case .debugWebsiteDataStoresCleared: return "m_d_wkwebsitedatastorescleared"
 
+            // MARK: Tab interaction state debug pixels
+
+        case .tabInteractionStateSourceMissingRootDirectory:
+            return "m_d_tab-interaction-state-source_missing-root-directory"
+        case .tabInteractionStateSourceFailedToWrite:
+            return "m_d_tab-interaction-state-source_failed-to-write"
+
+        case .tabInteractionStateFailedToRestore:
+            return "m_d_tab-interaction-state_failed-to-restore"
+        case .tabInteractionStateRestorationTime(let aggregation):
+            return "m_d_tab-interaction-state_restoration-time-\(aggregation)"
+
             // MARK: Ad Attribution
-            
+
         case .adAttributionGlobalAttributedRulesDoNotExist: return "m_attribution_global_attributed_rules_do_not_exist"
         case .adAttributionCompilationFailedForAttributedRulesList: return "m_attribution_compilation_failed_for_attributed_rules_list"
 

Core/UserDefaultsPropertyWrapper.swift

@@ -173,6 +173,7 @@ public struct UserDefaultsWrapper<T> {
         // Debug keys
         case debugNewTabPageSectionsEnabledKey = "com.duckduckgo.ios.debug.newTabPageSectionsEnabled"
         case debugOnboardingHighlightsEnabledKey = "com.duckduckgo.ios.debug.onboardingHighlightsEnabled"
+        case debugWebViewStateRestorationEnabledKey = "com.duckduckgo.ios.debug.webViewStateRestorationEnabled"
 
         // Duck Player Pixel Experiment
         case duckPlayerPixelExperimentInstalled = "com.duckduckgo.ios.duckplayer.pixel.experiment.installed.v2"

DuckDuckGo.xcodeproj/project.pbxproj

@@ -313,6 +313,9 @@
 		6F03CB092C32F331004179A8 /* PixelFiringAsync.swift in Sources */ = {isa = PBXBuildFile; fileRef = 6F03CB082C32F331004179A8 /* PixelFiringAsync.swift */; };
 		6F0FEF6B2C516D540090CDE4 /* NewTabPageSettingsStorage.swift in Sources */ = {isa = PBXBuildFile; fileRef = 6F0FEF6A2C516D540090CDE4 /* NewTabPageSettingsStorage.swift */; };
 		6F0FEF6D2C52639E0090CDE4 /* ReorderableForEach.swift in Sources */ = {isa = PBXBuildFile; fileRef = 6F0FEF6C2C52639E0090CDE4 /* ReorderableForEach.swift */; };
+		6F1422822D314A5300B6D3DE /* TabInteractionStateDiskSource.swift in Sources */ = {isa = PBXBuildFile; fileRef = 6F1422812D314A5300B6D3DE /* TabInteractionStateDiskSource.swift */; };
+		6F1422842D314DD100B6D3DE /* TabInteractionStateDiskSourceTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 6F1422832D314DC900B6D3DE /* TabInteractionStateDiskSourceTests.swift */; };
+		6F1422862D31509500B6D3DE /* MockDataExtensions.swift in Sources */ = {isa = PBXBuildFile; fileRef = 6F1422852D31509000B6D3DE /* MockDataExtensions.swift */; };
 		6F3529FF2CDCEDFF00A59170 /* OmniBarLoadingStateBearerTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 6F3529FE2CDCEDF700A59170 /* OmniBarLoadingStateBearerTests.swift */; };
 		6F35379E2C4AAF2E009F8717 /* NewTabPageSettingsView.swift in Sources */ = {isa = PBXBuildFile; fileRef = 6F35379D2C4AAF2E009F8717 /* NewTabPageSettingsView.swift */; };
 		6F3537A02C4AAFD2009F8717 /* NewTabPageSettingsSectionItemView.swift in Sources */ = {isa = PBXBuildFile; fileRef = 6F35379F2C4AAFD2009F8717 /* NewTabPageSettingsSectionItemView.swift */; };
@@ -332,6 +335,9 @@
 		6F64AA5F2C49463C00CF4489 /* ShortcutsModel.swift in Sources */ = {isa = PBXBuildFile; fileRef = 6F64AA5E2C49463C00CF4489 /* ShortcutsModel.swift */; };
 		6F655BE22BAB289E00AC3597 /* DefaultTheme.swift in Sources */ = {isa = PBXBuildFile; fileRef = 6F655BE12BAB289E00AC3597 /* DefaultTheme.swift */; };
 		6F691CCA2C4979EC002E9553 /* FavoritesTooltip.swift in Sources */ = {isa = PBXBuildFile; fileRef = 6F691CC92C4979EC002E9553 /* FavoritesTooltip.swift */; };
+		6F72353D2D3EBCB800710C07 /* WebViewStateRestorationDebugView.swift in Sources */ = {isa = PBXBuildFile; fileRef = 6F72353C2D3EBCB000710C07 /* WebViewStateRestorationDebugView.swift */; };
+		6F72353F2D3EC11E00710C07 /* WebViewStateRestorationManager.swift in Sources */ = {isa = PBXBuildFile; fileRef = 6F72353E2D3EC11500710C07 /* WebViewStateRestorationManager.swift */; };
+		6F7235412D3F974600710C07 /* MockTabInteractionStateSource.swift in Sources */ = {isa = PBXBuildFile; fileRef = 6F7235402D3F973C00710C07 /* MockTabInteractionStateSource.swift */; };
 		6F7BACD42CEE084B00F561D8 /* OmniBarEqualityCheckTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 6F7BACD32CEE084100F561D8 /* OmniBarEqualityCheckTests.swift */; };
 		6F7FB8E12C660B3E00867DA7 /* NewTabPageFavoritesModelTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 6F7FB8DF2C660B1A00867DA7 /* NewTabPageFavoritesModelTests.swift */; };
 		6F7FB8E32C660BF300867DA7 /* DailyPixelFiring.swift in Sources */ = {isa = PBXBuildFile; fileRef = 6F7FB8E22C660BF300867DA7 /* DailyPixelFiring.swift */; };
@@ -1715,6 +1721,9 @@
 		6F03CB082C32F331004179A8 /* PixelFiringAsync.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = PixelFiringAsync.swift; sourceTree = "<group>"; };
 		6F0FEF6A2C516D540090CDE4 /* NewTabPageSettingsStorage.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = NewTabPageSettingsStorage.swift; sourceTree = "<group>"; };
 		6F0FEF6C2C52639E0090CDE4 /* ReorderableForEach.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ReorderableForEach.swift; sourceTree = "<group>"; };
+		6F1422812D314A5300B6D3DE /* TabInteractionStateDiskSource.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = TabInteractionStateDiskSource.swift; sourceTree = "<group>"; };
+		6F1422832D314DC900B6D3DE /* TabInteractionStateDiskSourceTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = TabInteractionStateDiskSourceTests.swift; sourceTree = "<group>"; };
+		6F1422852D31509000B6D3DE /* MockDataExtensions.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = MockDataExtensions.swift; sourceTree = "<group>"; };
 		6F3529FE2CDCEDF700A59170 /* OmniBarLoadingStateBearerTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = OmniBarLoadingStateBearerTests.swift; sourceTree = "<group>"; };
 		6F35379D2C4AAF2E009F8717 /* NewTabPageSettingsView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = NewTabPageSettingsView.swift; sourceTree = "<group>"; };
 		6F35379F2C4AAFD2009F8717 /* NewTabPageSettingsSectionItemView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = NewTabPageSettingsSectionItemView.swift; sourceTree = "<group>"; };
@@ -1734,6 +1743,9 @@
 		6F64AA5E2C49463C00CF4489 /* ShortcutsModel.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ShortcutsModel.swift; sourceTree = "<group>"; };
 		6F655BE12BAB289E00AC3597 /* DefaultTheme.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = DefaultTheme.swift; sourceTree = "<group>"; };
 		6F691CC92C4979EC002E9553 /* FavoritesTooltip.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FavoritesTooltip.swift; sourceTree = "<group>"; };
+		6F72353C2D3EBCB000710C07 /* WebViewStateRestorationDebugView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = WebViewStateRestorationDebugView.swift; sourceTree = "<group>"; };
+		6F72353E2D3EC11500710C07 /* WebViewStateRestorationManager.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = WebViewStateRestorationManager.swift; sourceTree = "<group>"; };
+		6F7235402D3F973C00710C07 /* MockTabInteractionStateSource.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = MockTabInteractionStateSource.swift; sourceTree = "<group>"; };
 		6F7BACD32CEE084100F561D8 /* OmniBarEqualityCheckTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = OmniBarEqualityCheckTests.swift; sourceTree = "<group>"; };
 		6F7FB8DF2C660B1A00867DA7 /* NewTabPageFavoritesModelTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = NewTabPageFavoritesModelTests.swift; sourceTree = "<group>"; };
 		6F7FB8E22C660BF300867DA7 /* DailyPixelFiring.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = DailyPixelFiring.swift; sourceTree = "<group>"; };
@@ -4779,6 +4791,7 @@
 				D6F93E3B2B4FFA97004C268D /* SubscriptionDebugViewController.swift */,
 				8590CB602684D0600089F6BF /* CookieDebugViewController.swift */,
 				31206F6F2D3804E800A95D76 /* AIChatDebugView.swift */,
+				6F72353C2D3EBCB000710C07 /* WebViewStateRestorationDebugView.swift */,
 				4B0295182537BC6700E00CEF /* ConfigurationDebugViewController.swift */,
 				858566FA252E55D6007501B8 /* ImageCacheDebugViewController.swift */,
 				8590CB66268A2E520089F6BF /* RootDebugViewController.swift */,
@@ -6306,6 +6319,8 @@
 		F13B4BF41F18C74500814661 /* Tabs */ = {
 			isa = PBXGroup;
 			children = (
+				6F72353E2D3EC11500710C07 /* WebViewStateRestorationManager.swift */,
+				6F1422812D314A5300B6D3DE /* TabInteractionStateDiskSource.swift */,
 				8565A34A1FC8D96B00239327 /* LaunchTabNotification.swift */,
 				F1617C141E57336D00DEDCAF /* TabManager.swift */,
 				F13B4BF51F18C75D00814661 /* Model */,
@@ -6355,6 +6370,7 @@
 		F13B4BF71F18C9E800814661 /* Tabs */ = {
 			isa = PBXGroup;
 			children = (
+				6F1422832D314DC900B6D3DE /* TabInteractionStateDiskSourceTests.swift */,
 				6FF9AD402CE6610600C5A406 /* TabSwitcherOpenDailyPixelTests.swift */,
 				85010503292FFB080033978F /* FireproofFaviconUpdaterTests.swift */,
 				8565A34C1FC8DFE400239327 /* LaunchTabNotificationTests.swift */,
@@ -6506,6 +6522,8 @@
 		F17669A91E412A17003D3222 /* Mocks */ = {
 			isa = PBXGroup;
 			children = (
+				6F7235402D3F973C00710C07 /* MockTabInteractionStateSource.swift */,
+				6F1422852D31509000B6D3DE /* MockDataExtensions.swift */,
 				85C503FE2CF0F4D60075DF6F /* MockWebsiteDataManager.swift */,
 				8598D2E52CEBAA1B00C45685 /* MockFaviconStore.swift */,
 				9F4CC51A2C48C0C7006A96EB /* MockTabDelegate.swift */,
@@ -8220,6 +8238,7 @@
 				6FDC64052C98515E00DB71B3 /* FavoriteAddItemView.swift in Sources */,
 				982686AD2600C0850011A8D6 /* ActionMessageView.swift in Sources */,
 				D6E0C1852B7A2B9400D5E1E9 /* DesktopDownloadPlatformConstants.swift in Sources */,
+				6F72353D2D3EBCB800710C07 /* WebViewStateRestorationDebugView.swift in Sources */,
 				9F8E0F312CCA6390001EA7C5 /* AddToDockTutorialView.swift in Sources */,
 				D6BFCB5F2B7524AA0051FF81 /* SubscriptionPIRView.swift in Sources */,
 				9F8E0F2F2CCA6202001EA7C5 /* VideoPlayerViewModel.swift in Sources */,
@@ -8350,6 +8369,7 @@
 				D6E83C312B1EA309006C8AFB /* SettingsCell.swift in Sources */,
 				1DEAADEE2BA45DFE00E25A97 /* SettingsDataClearingView.swift in Sources */,
 				6F96FF102C2B128500162692 /* NewTabPageCustomizeButtonView.swift in Sources */,
+				6F1422822D314A5300B6D3DE /* TabInteractionStateDiskSource.swift in Sources */,
 				EE01EB432AFC1E0A0096AAC9 /* NetworkProtectionVPNLocationView.swift in Sources */,
 				7BC571202BDBB877003B0CCE /* VPNActivationDateStore.swift in Sources */,
 				9820EAF522613CD30089094D /* WebProgressWorker.swift in Sources */,
@@ -8395,6 +8415,7 @@
 				85C2971A248162CA0063A335 /* DaxOnboardingPadViewController.swift in Sources */,
 				F4F6DFB826EA9AA600ED7E12 /* BookmarksTextFieldCell.swift in Sources */,
 				6FE127402C204D9B00EB5724 /* ShortcutsView.swift in Sources */,
+				6F72353F2D3EC11E00710C07 /* WebViewStateRestorationManager.swift in Sources */,
 				85F98F92296F32BD00742F4A /* SyncSettingsViewController.swift in Sources */,
 				84E341961E2F7EFB00BDBA6F /* AppDelegate.swift in Sources */,
 				310D091D2799F57200DC0060 /* Download.swift in Sources */,
@@ -8613,6 +8634,7 @@
 				987130C5294AAB9F00AB05E0 /* BookmarkEditorViewModelTests.swift in Sources */,
 				BDFF03262BA3DA4900F324C9 /* NetworkProtectionFeatureVisibilityTests.swift in Sources */,
 				9F8E0F332CCA642D001EA7C5 /* VideoPlayerViewModelTests.swift in Sources */,
+				6F1422842D314DD100B6D3DE /* TabInteractionStateDiskSourceTests.swift in Sources */,
 				D62EC3BA2C246A7000FC9D04 /* YoutublePlayerNavigationHandlerTests.swift in Sources */,
 				1EAABE712C99FC75003F5137 /* SubscriptionFeatureAvailabilityMock.swift in Sources */,
 				8341D807212D5E8D000514C2 /* HashExtensionTest.swift in Sources */,
@@ -8663,6 +8685,7 @@
 				56A061442BEE086700F24B36 /* CapturingAdapterErrorHandler.swift in Sources */,
 				C1BF0BA929B63E2200482B73 /* AutofillLoginPromptViewModelTests.swift in Sources */,
 				EE3B226B29DE0F110082298A /* MockInternalUserStoring.swift in Sources */,
+				6F1422862D31509500B6D3DE /* MockDataExtensions.swift in Sources */,
 				852409312C78030D00CB28FC /* MockUsageSegmentation.swift in Sources */,
 				987130C8294AAB9F00AB05E0 /* BookmarksTestHelpers.swift in Sources */,
 				9F4CC51D2C48D240006A96EB /* CoreDataDatabaseTestUtilities.swift in Sources */,
@@ -8696,6 +8719,7 @@
 				C1935A222C89CA9F001AD72D /* AutofillSurveyManagerTests.swift in Sources */,
 				22CB1ED8203DDD2C00D2C724 /* AppDeepLinksTests.swift in Sources */,
 				9847C00527A41A0A00DB07AA /* WebViewTestHelper.swift in Sources */,
+				6F7235412D3F974600710C07 /* MockTabInteractionStateSource.swift in Sources */,
 				3170048227A9504F00C03F35 /* DownloadMocks.swift in Sources */,
 				317045C02858C6B90016ED1F /* AutofillInterfaceEmailTruncatorTests.swift in Sources */,
 				6FD3AEE32B8F4EEB0060FCCC /* AdAttributionPixelReporterTests.swift in Sources */,

DuckDuckGo/AppLifecycle/AppStates/Launching.swift

@@ -449,6 +449,11 @@ struct Launching: AppState {
                 await autoClear.clearDataIfEnabled(applicationState: .init(with: applicationState))
                 await vpnWorkaround.installRedditSessionWorkaround()
             }
+
+            if !autoClear.isClearingEnabled {
+                // If not using autoclear, make sure there are no leftover states on disk.
+                mainViewController?.tabManager.removeLeftoverInteractionStates()
+            }
         }
         unService = UNService(window: window, accountManager: accountManager)
         uiService = UIService(window: window)