Added JS event listener for tab web-state.

Client.xcodeproj/project.pbxproj

@@ -1057,6 +1057,8 @@
 		CA225DF72795D1A80024C104 /* MainFrameAtDocumentEndSandboxed.js in Resources */ = {isa = PBXBuildFile; fileRef = CA225DF52795D1A80024C104 /* MainFrameAtDocumentEndSandboxed.js */; };
 		CA225DF92795D7690024C104 /* WKContentWorld+Sandbox.swift in Sources */ = {isa = PBXBuildFile; fileRef = CA225DF82795D7690024C104 /* WKContentWorld+Sandbox.swift */; };
 		CA29F2F3273DAEA100C391C3 /* PlaylistOnboardingView.swift in Sources */ = {isa = PBXBuildFile; fileRef = CA29F2F2273DAEA100C391C3 /* PlaylistOnboardingView.swift */; };
+		CA2CA1B127F4B50300B25646 /* ReadyState.js in Resources */ = {isa = PBXBuildFile; fileRef = CA2CA1B027F4B50300B25646 /* ReadyState.js */; };
+		CA2CA1CF27F4B93400B25646 /* ReadyStateScriptHelper.swift in Sources */ = {isa = PBXBuildFile; fileRef = CA2CA1CE27F4B93400B25646 /* ReadyStateScriptHelper.swift */; };
 		CA2EE0A527349E970089C75F /* disconnect-entitylist.json in Resources */ = {isa = PBXBuildFile; fileRef = CA2EE09927349E970089C75F /* disconnect-entitylist.json */; };
 		CA2EE0A727349F760089C75F /* OnboardingAdblockDisconnect.swift in Sources */ = {isa = PBXBuildFile; fileRef = CA2EE0A627349F760089C75F /* OnboardingAdblockDisconnect.swift */; };
 		CA439A5925E6F29D00FE9150 /* VideoPlayerInfoBar.swift in Sources */ = {isa = PBXBuildFile; fileRef = CA439A5825E6F29D00FE9150 /* VideoPlayerInfoBar.swift */; };
@@ -3014,6 +3016,8 @@
 		CA225DF52795D1A80024C104 /* MainFrameAtDocumentEndSandboxed.js */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.javascript; path = MainFrameAtDocumentEndSandboxed.js; sourceTree = "<group>"; };
 		CA225DF82795D7690024C104 /* WKContentWorld+Sandbox.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "WKContentWorld+Sandbox.swift"; sourceTree = "<group>"; };
 		CA29F2F2273DAEA100C391C3 /* PlaylistOnboardingView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = PlaylistOnboardingView.swift; sourceTree = "<group>"; };
+		CA2CA1B027F4B50300B25646 /* ReadyState.js */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.javascript; path = ReadyState.js; sourceTree = "<group>"; };
+		CA2CA1CE27F4B93400B25646 /* ReadyStateScriptHelper.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ReadyStateScriptHelper.swift; sourceTree = "<group>"; };
 		CA2EE09927349E970089C75F /* disconnect-entitylist.json */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = text.json; path = "disconnect-entitylist.json"; sourceTree = "<group>"; };
 		CA2EE0A627349F760089C75F /* OnboardingAdblockDisconnect.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = OnboardingAdblockDisconnect.swift; sourceTree = "<group>"; };
 		CA439A5825E6F29D00FE9150 /* VideoPlayerInfoBar.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = VideoPlayerInfoBar.swift; sourceTree = "<group>"; };
@@ -4833,6 +4837,7 @@
 				D31F95E81AC226CB005C9F3B /* ScreenshotHelper.swift */,
 				F35B8D2C1D6383E9008E3D61 /* SessionRestoreHelper.swift */,
 				5E4845C122DE3DF800372022 /* WindowRenderHelperScript.swift */,
+				CA2CA1CE27F4B93400B25646 /* ReadyStateScriptHelper.swift */,
 			);
 			path = Helpers;
 			sourceTree = "<group>";
@@ -6064,6 +6069,7 @@
 				5EC2C0E425C0B321005EA984 /* PlaylistDetector.js */,
 				5EC0017D260129AC005DDE4A /* PlaylistSwizzler.js */,
 				CA55048F269DED8F00C19917 /* MediaBackgrounding.js */,
+				CA2CA1B027F4B50300B25646 /* ReadyState.js */,
 			);
 			path = UserScripts;
 			sourceTree = "<group>";
@@ -7732,6 +7738,7 @@
 				CA225DF22795CECE0024C104 /* MainFrame.js in Resources */,
 				4481F23626CBD27B00658EAC /* GlobalSignRootCA_E46.cer in Resources */,
 				4422D55221BFFB7E00BF1855 /* make_unicode_casefold.py in Resources */,
+				CA2CA1B127F4B50300B25646 /* ReadyState.js in Resources */,
 				5E4E078324A0E4D700B01720 /* YoutubeAdblock.js in Resources */,
 				445ABC962731DDFF0089710D /* NewYorkMedium-Bold.otf in Resources */,
 				E4B7B7791A793CF20022C5E0 /* FiraSans-Light.ttf in Resources */,
@@ -8440,6 +8447,7 @@
 				27FD2CAB2146C31C00A5A779 /* RequestDesktopSiteActivity.swift in Sources */,
 				3BCE6D3C1CEB9E4D0080928C /* ThirdPartySearchAlerts.swift in Sources */,
 				4422D55A21BFFB7F00BF1855 /* regexp.cc in Sources */,
+				CA2CA1CF27F4B93400B25646 /* ReadyStateScriptHelper.swift in Sources */,
 				0A7B5D722269E7AD00AADF22 /* BookmarkEditMode.swift in Sources */,
 				4422D4DC21BFFB7600BF1855 /* block_builder.cc in Sources */,
 				27201EFE24539B5500C19DD1 /* NewTabPageBackground.swift in Sources */,

Client/Frontend/Browser/BrowserViewController.swift

@@ -2046,6 +2046,7 @@ extension BrowserViewController: TabDelegate {
 
     tab.addContentScript(RewardsReporting(rewards: rewards, tab: tab), name: RewardsReporting.name(), contentWorld: .page)
     tab.addContentScript(AdsMediaReporting(rewards: rewards, tab: tab), name: AdsMediaReporting.name(), contentWorld: .defaultClient)
+    tab.addContentScript(ReadyStateScriptHelper(tab: tab), name: ReadyStateScriptHelper.name(), contentWorld: .page)
   }
 
   func tab(_ tab: Tab, willDeleteWebView webView: WKWebView) {

Client/Frontend/Browser/Helpers/ReadyStateScriptHelper.swift

@@ -0,0 +1,82 @@
+// Copyright 2022 The Brave Authors. All rights reserved.
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+import Foundation
+import Shared
+import WebKit
+
+private let log = Logger.browserLogger
+
+struct ReadyState: Codable {
+  let securityToken: String
+  let state: State
+
+  enum State: String, Codable {
+    // Page State
+    case loading
+    case interactive
+    case complete
+    case loaded
+
+    // History State
+    case pushstate
+    case replacestate
+    case popstate
+  }
+
+  public static func from(message: WKScriptMessage) -> ReadyState? {
+    if !JSONSerialization.isValidJSONObject(message.body) {
+      return nil
+    }
+
+    do {
+      let data = try JSONSerialization.data(withJSONObject: message.body, options: [])
+      return try JSONDecoder().decode(ReadyState.self, from: data)
+    } catch {
+      log.error("Error Decoding ReadyState: \(error)")
+    }
+
+    return nil
+  }
+
+  private enum CodingKeys: String, CodingKey {
+    case securityToken = "securitytoken"
+    case state
+  }
+}
+
+class ReadyStateScriptHelper: TabContentScript {
+  private weak var tab: Tab?
+  private var debounceTimer: Timer?
+
+  required init(tab: Tab) {
+    self.tab = tab
+  }
+
+  class func name() -> String {
+    return "ReadyStateScriptHelper"
+  }
+
+  func scriptMessageHandlerName() -> String? {
+    return "ReadyState_\(UserScriptManager.messageHandlerTokenString)"
+  }
+
+  func userContentController(_ userContentController: WKUserContentController, didReceiveScriptMessage message: WKScriptMessage, replyHandler: (Any?, String?) -> Void) {
+
+    defer { replyHandler(nil, nil) }
+
+    guard let readyState = ReadyState.from(message: message) else {
+      log.error("Invalid Ready State")
+      return
+    }
+
+    guard readyState.securityToken == UserScriptManager.securityTokenString else {
+      log.error("Invalid or Missing security token")
+      return
+    }
+
+    tab?.onPageReadyStateChanged?(readyState.state)
+  }
+}

Client/Frontend/Browser/Tab.swift

@@ -195,6 +195,8 @@ class Tab: NSObject {
   var screenshotUUID: UUID? {
     didSet { TabMO.saveScreenshotUUID(screenshotUUID, tabId: id) }
   }
+
+  var onPageReadyStateChanged: ((ReadyState.State) -> Void)?
 
   // If this tab has been opened from another, its parent will point to the tab from which it was opened
   var parent: Tab?

Client/Frontend/Browser/TabManager.swift

@@ -491,7 +491,27 @@ class TabManager: NSObject {
     if flushToDisk && !zombie && !isPrivate {
       saveTab(tab, saveOrder: true)
     }
-
+
+    // When the state of the page changes, we debounce a call to save the screenshots and tab information
+    // This fixes pages that have dynamic URL via changing history
+    // as well as regular pages that load DOM normally.
+    var debounce_timer: Timer?
+    tab.onPageReadyStateChanged = { [weak self] state in
+      guard let self = self else { return }
+
+      debounce_timer?.invalidate()
+      debounce_timer = Timer.scheduledTimer(withTimeInterval: 1.0, repeats: false) { _ in
+        debounce_timer?.invalidate()
+
+        if state == .complete || state == .loaded || state == .pushstate || state == .popstate {
+          // Saving Tab Private Mode - not supported yet.
+          if !tab.isPrivate {
+            self.preserveScreenshots()
+            self.saveTab(tab)
+          }
+        }
+      }
+    }
   }
 
   func indexOfWebView(_ webView: WKWebView) -> UInt? {

Client/Frontend/Browser/UserScriptManager.swift

@@ -363,6 +363,31 @@ class UserScriptManager {
       forMainFrameOnly: true,
       in: .defaultClient)
   }()
+
+  private let ReadyStateScript: WKUserScript? = {
+    guard let path = Bundle.main.path(forResource: "ReadyState", ofType: "js"), let source = try? String(contentsOfFile: path) else {
+      log.error("Failed to load ReadyState.js")
+      return nil
+    }
+
+    var alteredSource = source
+    let token = UserScriptManager.securityTokenString
+
+    let replacements = [
+      "$<security_token>": token,
+      "$<handler>": "ReadyState_\(messageHandlerTokenString)",
+    ]
+
+    replacements.forEach({
+      alteredSource = alteredSource.replacingOccurrences(of: $0.key, with: $0.value, options: .literal)
+    })
+
+    return WKUserScript.create(
+      source: alteredSource,
+      injectionTime: .atDocumentStart,
+      forMainFrameOnly: true,
+      in: .page)
+  }()
 
   private func reloadUserScripts() {
     tab?.webView?.configuration.userContentController.do {
@@ -403,6 +428,10 @@ class UserScriptManager {
       if isNightModeEnabled, let script = NightModeScript {
         $0.addUserScript(script)
       }
+
+      if let script = ReadyStateScript {
+        $0.addUserScript(script)
+      }
 
       if let domainUserScript = domainUserScript, let script = domainUserScript.script {
         $0.addUserScript(script)

Client/Frontend/UserContent/UserScripts/ReadyState.js

@@ -0,0 +1,77 @@
+// Copyright 2021 The Brave Authors. All rights reserved.
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+(function() {
+  // Listen for document ready state
+  document.addEventListener('readystatechange', (event) => {
+    window.webkit.messageHandlers.$<handler>.postMessage({
+      "securitytoken": "$<security_token>",
+      "state": document.readyState
+    });
+  });
+
+  // Listen for document load state
+  window.addEventListener('load', (event) => {
+    window.webkit.messageHandlers.$<handler>.postMessage({
+      "securitytoken": "$<security_token>",
+      "state": "loaded"
+    });
+  });
+
+  // Listen for history popped
+  window.addEventListener('popstate', (event) => {
+    if (event.state) {
+      // Run on the browser's next run-loop
+      setTimeout(() => {
+        window.webkit.messageHandlers.$<handler>.postMessage({
+          "securitytoken": "$<security_token>",
+          "state": "popstate"
+        });
+      }, 0);
+    }
+  });
+
+  // Listen for history pushed
+  const pushState = History.prototype.pushState;
+  History.prototype.pushState = function(state, unused, url) {
+    pushState.call(this, state, unused, url);
+
+    if (state) {
+      // Run on the browser's next run-loop
+      setTimeout(() => {
+        window.webkit.messageHandlers.$<handler>.postMessage({
+          "securitytoken": "$<security_token>",
+          "state": "pushstate"
+        });
+      }, 0);
+    }
+  };
+
+  // Listen for history replaced
+  const replaceState = History.prototype.replaceState;
+  History.prototype.replaceState = function(state, unused, url) {
+    replaceState.call(this, state, unused, url);
+
+    if (state) {
+      // Run on the browser's next run-loop
+      setTimeout(() => {
+        window.webkit.messageHandlers.$<handler>.postMessage({
+          "securitytoken": "$<security_token>",
+          "state": "replacestate"
+        });
+      }, 0);
+    }
+  };
+
+  // Hide the pushState trampoline
+  History.prototype.pushState.toString = function() {
+    return "function () { [native code] }";
+  };
+
+  // Hide the replaceState trampoline
+  History.prototype.replaceState.toString = function() {
+    return "function () { [native code] }";
+  };
+})();