fix(anki pages): don't crash after onRenderProcessGone

tested with the following patch:

```patch
Subject: [PATCH] testing
---
Index: AnkiDroid/src/main/java/com/ichi2/anki/previewer/CardViewerFragment.kt
IDEA additional info:
Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP
<+>UTF-8
===================================================================
diff --git a/AnkiDroid/src/main/java/com/ichi2/anki/previewer/CardViewerFragment.kt b/AnkiDroid/src/main/java/com/ichi2/anki/previewer/CardViewerFragment.kt
--- a/AnkiDroid/src/main/java/com/ichi2/anki/previewer/CardViewerFragment.kt	(revision a3e86d739bf9049cd6673076a1ec5bb2beeac4ee)
+++ b/AnkiDroid/src/main/java/com/ichi2/anki/previewer/CardViewerFragment.kt	(date 1762546566117)
@@ -37,6 +37,7 @@
 import com.ichi2.anki.R
 import com.ichi2.anki.ViewerResourceHandler
 import com.ichi2.anki.dialogs.TtsVoicesDialogFragment
+import com.ichi2.anki.launchCatchingTask
 import com.ichi2.anki.localizedErrorMessage
 import com.ichi2.anki.snackbar.showSnackbar
 import com.ichi2.anki.utils.ext.collectIn
@@ -48,6 +49,7 @@
 import com.ichi2.compat.CompatHelper.Companion.resolveActivityCompat
 import com.ichi2.themes.Themes
 import com.ichi2.utils.show
+import kotlinx.coroutines.delay
 import kotlinx.coroutines.flow.launchIn
 import kotlinx.coroutines.flow.onEach
 import timber.log.Timber
@@ -69,6 +71,13 @@
         viewModel.eval.collectIn(lifecycleScope) { eval ->
             webViewLayout.evaluateJavascript(eval)
         }
+
+        launchCatchingTask {
+            (0..2).forEach { _ ->
+                delay(3000)
+                webViewLayout.loadUrl("chrome://crash")
+            }
+        }
     }

     override fun onStart() {
Index: AnkiDroid/src/main/java/com/ichi2/anki/pages/PageFragment.kt
IDEA additional info:
Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP
<+>UTF-8
===================================================================
diff --git a/AnkiDroid/src/main/java/com/ichi2/anki/pages/PageFragment.kt b/AnkiDroid/src/main/java/com/ichi2/anki/pages/PageFragment.kt
--- a/AnkiDroid/src/main/java/com/ichi2/anki/pages/PageFragment.kt	(revision a3e86d739bf9049cd6673076a1ec5bb2beeac4ee)
+++ b/AnkiDroid/src/main/java/com/ichi2/anki/pages/PageFragment.kt	(date 1762546610210)
@@ -31,9 +31,11 @@
 import com.google.android.material.progressindicator.CircularProgressIndicator
 import com.ichi2.anki.R
 import com.ichi2.anki.SingleFragmentActivity
+import com.ichi2.anki.launchCatchingTask
 import com.ichi2.anki.workarounds.OnWebViewRecreatedListener
 import com.ichi2.anki.workarounds.SafeWebViewLayout
 import com.ichi2.themes.Themes
+import kotlinx.coroutines.delay
 import timber.log.Timber
 import kotlin.reflect.KClass

@@ -118,6 +120,13 @@
         }

         setupWebView(savedInstanceState)
+
+        launchCatchingTask {
+            (0..2).forEach { _ ->
+                delay(3000)
+                webViewLayout.loadUrl("chrome://crash")
+            }
+        }
     }

     private fun setupWebView(savedInstanceState: Bundle?) {
```

Author: BrayanDSO

AnkiDroid/src/main/java/com/ichi2/anki/pages/CongratsPage.kt

@@ -76,7 +76,7 @@ class CongratsPage :
         // typically due to 'day rollover'
         if (changes.studyQueues) {
             Timber.i("refreshing: study queues updated")
-            webView.reload()
+            webViewLayout.reload()
         }
     }
 

AnkiDroid/src/main/java/com/ichi2/anki/pages/DeckOptions.kt

@@ -57,7 +57,7 @@ class DeckOptions : PageFragment() {
         object : OnBackPressedCallback(false) {
             override fun handleOnBackPressed() {
                 Timber.v("webView: navigating back")
-                webView.goBack()
+                webViewLayout.goBack()
             }
         }
 
@@ -71,7 +71,7 @@ class DeckOptions : PageFragment() {
             override fun handleOnBackPressed() {
                 Timber.v("DeckOptions: requesting the webview to handle the user close request.")
                 if (webViewIsReady) {
-                    webView.evaluateJavascript("anki.deckOptionsPendingChanges()") {
+                    webViewLayout.evaluateJavascript("anki.deckOptionsPendingChanges()") {
                         // Callback is handled in the WebView:
                         //  * A 'discard changes' dialog may be shown, using confirm()
                         //  * if no changes, or changes discarded, `deckOptionsRequireClose` is called
@@ -115,7 +115,7 @@ class DeckOptions : PageFragment() {
             override fun handleOnBackPressed() {
                 Timber.i("back button: closing displayed modal")
                 try {
-                    webView.evaluateJavascript(
+                    webViewLayout.evaluateJavascript(
                         """
                         document.getElementsByClassName("modal show")[0]
                         .getElementsByClassName("btn-close")[0].click()
@@ -160,18 +160,18 @@ class DeckOptions : PageFragment() {
         super.onViewCreated(view, savedInstanceState)
     }
 
-    override fun onWebViewCreated(webView: WebView) {
+    override fun onWebViewCreated() {
         // addJavascriptInterface needs to happen before loadUrl
-        webView.addJavascriptInterface(ModalJavaScriptInterfaceListener(), "ankidroid")
+        webViewLayout.addJavascriptInterface(ModalJavaScriptInterfaceListener(), "ankidroid")
         Timber.d("Added JS Interface: 'ankidroid")
     }
 
     @NeedsTest("going back on a manual page takes priority over closing a modal")
     override fun onCreateWebViewClient(savedInstanceState: Bundle?): PageWebViewClient {
-        requireActivity().onBackPressedDispatcher.addCallback(this, onBackFromDeckOptions)
-        requireActivity().onBackPressedDispatcher.addCallback(this, onBackFromModal)
+        activity?.onBackPressedDispatcher?.addCallback(this, onBackFromDeckOptions)
+        activity?.onBackPressedDispatcher?.addCallback(this, onBackFromModal)
         // going back on a manual page takes priority over closing a modal
-        requireActivity().onBackPressedDispatcher.addCallback(this, onBackFromManual)
+        activity?.onBackPressedDispatcher?.addCallback(this, onBackFromManual)
 
         return object : PageWebViewClient() {
             private val ankiManualHostRegex = Regex("^docs\\.ankiweb\\.net\$")
@@ -228,14 +228,14 @@ class DeckOptions : PageFragment() {
         val openJs = getListenerJs("shown.bs.modal", "open")
         val closeJs = getListenerJs("hidden.bs.modal", "close")
 
-        webView.evaluateJavascript(openJs, {})
-        webView.evaluateJavascript(closeJs, {})
+        webViewLayout.evaluateJavascript(openJs, {})
+        webViewLayout.evaluateJavascript(closeJs, {})
     }
 
     fun onWebViewReady() {
         Timber.d("WebView ready to receive input")
         webViewIsReady = true
-        webView.isVisible = true
+        webViewLayout.isVisible = true
         pageLoadingIndicator.isVisible = false
     }
 

AnkiDroid/src/main/java/com/ichi2/anki/pages/ImageOcclusion.kt

@@ -75,7 +75,7 @@ class ImageOcclusion :
         view.findViewById<MaterialToolbar>(R.id.toolbar).setOnMenuItemClickListener {
             if (it.itemId == R.id.action_save) {
                 Timber.i("save item selected")
-                webView.evaluateJavascript("anki.imageOcclusion.save()") {
+                webViewLayout.evaluateJavascript("anki.imageOcclusion.save()") {
                     // reset to the previous deck that the backend "saw" as selected, this
                     // avoids other screens unexpectedly having their working decks modified(
                     // most important being the Reviewer where the user would find itself

AnkiDroid/src/main/java/com/ichi2/anki/pages/PageFragment.kt

@@ -31,6 +31,8 @@ import com.google.android.material.appbar.MaterialToolbar
 import com.google.android.material.progressindicator.CircularProgressIndicator
 import com.ichi2.anki.R
 import com.ichi2.anki.SingleFragmentActivity
+import com.ichi2.anki.workarounds.OnWebViewRecreatedListener
+import com.ichi2.anki.workarounds.SafeWebViewLayout
 import com.ichi2.themes.Themes
 import timber.log.Timber
 import kotlin.reflect.KClass
@@ -41,8 +43,9 @@ import kotlin.reflect.KClass
 open class PageFragment(
     @LayoutRes contentLayoutId: Int = R.layout.page_fragment,
 ) : Fragment(contentLayoutId),
-    PostRequestHandler {
-    lateinit var webView: WebView
+    PostRequestHandler,
+    OnWebViewRecreatedListener {
+    lateinit var webViewLayout: SafeWebViewLayout
     private lateinit var server: AnkiServer
 
     /**
@@ -63,7 +66,7 @@ open class PageFragment(
      */
     protected open fun onCreateWebViewClient(savedInstanceState: Bundle?) = PageWebViewClient()
 
-    protected open fun onWebViewCreated(webView: WebView) { }
+    protected open fun onWebViewCreated() { }
 
     /**
      * When the webview calls `BridgeCommand("foo")`, the PageFragment execute `bridgeCommands["foo"]`.
@@ -78,7 +81,7 @@ open class PageFragment(
         if (bridgeCommands.isEmpty()) {
             return
         }
-        webView.addJavascriptInterface(
+        webViewLayout.addJavascriptInterface(
             object : Any() {
                 @JavascriptInterface
                 fun bridgeCommandImpl(request: String) {
@@ -101,39 +104,42 @@ open class PageFragment(
         view: View,
         savedInstanceState: Bundle?,
     ) {
-        val pageWebViewClient = onCreateWebViewClient(savedInstanceState)
         server = AnkiServer(this).also { it.start() }
-        webView =
-            view.findViewById<WebView>(R.id.webview).apply {
-                with(settings) {
-                    javaScriptEnabled = true
-                    displayZoomControls = false
-                    builtInZoomControls = true
-                    setSupportZoom(true)
-                }
-                webViewClient = pageWebViewClient
-                webChromeClient = PageChromeClient()
-            }
-        setupBridgeCommand(pageWebViewClient)
-        onWebViewCreated(webView)
-
-        val arguments = requireArguments()
-        val path = requireNotNull(arguments.getString(PATH_ARG_KEY)) { "'$PATH_ARG_KEY' missing" }
-        val title = arguments.getString(TITLE_ARG_KEY)
-
-        val nightMode = if (Themes.currentTheme.isNightMode) "#night" else ""
-        val url = "${server.baseUrl()}$path$nightMode".toUri()
-        Timber.i("Loading $url")
-        webView.loadUrl(url.toString())
+        webViewLayout = view.findViewById(R.id.webview_layout)
 
-        view.findViewById<MaterialToolbar>(R.id.toolbar).apply {
+        val title = requireArguments().getString(TITLE_ARG_KEY)
+        view.findViewById<MaterialToolbar>(R.id.toolbar)?.apply {
             if (title != null) {
                 setTitle(title)
             }
             setNavigationOnClickListener {
                 requireActivity().onBackPressedDispatcher.onBackPressed()
             }
         }
+
+        setupWebView(savedInstanceState)
+    }
+
+    private fun setupWebView(savedInstanceState: Bundle?) {
+        val pageWebViewClient = onCreateWebViewClient(savedInstanceState)
+        webViewLayout.apply {
+            setAcceptThirdPartyCookies(true)
+            with(settings) {
+                javaScriptEnabled = true
+                displayZoomControls = false
+                builtInZoomControls = true
+                setSupportZoom(true)
+            }
+            setWebViewClient(pageWebViewClient)
+            setWebChromeClient(PageChromeClient())
+            setupBridgeCommand(pageWebViewClient)
+            onWebViewCreated()
+        }
+        val path = requireNotNull(requireArguments().getString(PATH_ARG_KEY)) { "'$PATH_ARG_KEY' missing" }
+        val nightMode = if (Themes.currentTheme.isNightMode) "#night" else ""
+        val url = "${server.baseUrl()}$path$nightMode".toUri()
+        Timber.i("Loading $url")
+        webViewLayout.loadUrl(url.toString())
     }
 
     override suspend fun handlePostRequest(
@@ -156,6 +162,10 @@ open class PageFragment(
         super.onDestroyView()
     }
 
+    override fun onWebViewRecreated(webView: WebView) {
+        setupWebView(null)
+    }
+
     companion object {
         const val PATH_ARG_KEY = "path"
         const val TITLE_ARG_KEY = "title"

AnkiDroid/src/main/java/com/ichi2/anki/pages/PageWebViewClient.kt

@@ -20,10 +20,11 @@ import android.webkit.ValueCallback
 import android.webkit.WebResourceRequest
 import android.webkit.WebResourceResponse
 import android.webkit.WebView
-import android.webkit.WebViewClient
 import androidx.core.view.isVisible
 import com.google.android.material.color.MaterialColors
 import com.ichi2.anki.OnPageFinishedCallback
+import com.ichi2.anki.workarounds.SafeWebViewClient
+import com.ichi2.anki.workarounds.SafeWebViewLayout
 import com.ichi2.utils.AssetHelper.guessMimeType
 import com.ichi2.utils.toRGBHex
 import timber.log.Timber
@@ -33,7 +34,7 @@ import java.io.IOException
 /**
  * Base WebViewClient to be used on [PageFragment]
  */
-open class PageWebViewClient : WebViewClient() {
+open class PageWebViewClient : SafeWebViewClient() {
     val onPageFinishedCallbacks: MutableList<OnPageFinishedCallback> = mutableListOf()
 
     override fun shouldInterceptRequest(
@@ -93,6 +94,7 @@ open class PageWebViewClient : WebViewClient() {
     open fun onShowWebView(webView: WebView) {
         Timber.v("Displaying WebView")
         webView.isVisible = true
+        (webView.parent as? SafeWebViewLayout)?.isVisible = true
     }
 
     override fun onPageFinished(

AnkiDroid/src/main/java/com/ichi2/anki/pages/RemoveAccountFragment.kt

@@ -20,13 +20,14 @@ import android.os.Bundle
 import android.view.View
 import android.webkit.WebResourceRequest
 import android.webkit.WebView
-import android.webkit.WebViewClient
 import androidx.annotation.CallSuper
 import androidx.core.view.isVisible
 import androidx.fragment.app.Fragment
 import com.google.android.material.appbar.MaterialToolbar
 import com.ichi2.anki.R
 import com.ichi2.anki.common.annotations.NeedsTest
+import com.ichi2.anki.workarounds.SafeWebViewClient
+import com.ichi2.anki.workarounds.SafeWebViewLayout
 import timber.log.Timber
 
 /**
@@ -48,7 +49,7 @@ import timber.log.Timber
  */
 @NeedsTest("pressing 'back' on this screen closes it")
 class RemoveAccountFragment : Fragment(R.layout.page_fragment) {
-    private lateinit var webView: WebView
+    private lateinit var webViewLayout: SafeWebViewLayout
 
     /**
      * A count of the redirects performed, to ensure we don't get into an infinite loop
@@ -70,7 +71,7 @@ class RemoveAccountFragment : Fragment(R.layout.page_fragment) {
         }
 
         Timber.i("redirecting to 'remove account'")
-        webView.loadUrl(getString(R.string.remove_account_url))
+        webViewLayout.loadUrl(getString(R.string.remove_account_url))
         return true
     }
 
@@ -79,17 +80,17 @@ class RemoveAccountFragment : Fragment(R.layout.page_fragment) {
         view: View,
         savedInstanceState: Bundle?,
     ) {
-        webView =
-            view.findViewById<WebView>(R.id.webview).apply {
+        webViewLayout =
+            view.findViewById<SafeWebViewLayout>(R.id.webview_layout).apply {
                 isVisible = true
                 with(settings) {
                     javaScriptEnabled = true
                     displayZoomControls = false
                     builtInZoomControls = true
                     setSupportZoom(true)
                 }
-                webViewClient =
-                    object : WebViewClient() {
+                val webViewClient =
+                    object : SafeWebViewClient() {
                         override fun shouldOverrideUrlLoading(
                             view: WebView?,
                             request: WebResourceRequest?,
@@ -119,12 +120,13 @@ class RemoveAccountFragment : Fragment(R.layout.page_fragment) {
                             maybeRedirectToRemoveAccount(url)
                         }
                     }
+                setWebViewClient(webViewClient)
             }
 
         // BUG: custom sync server doesn't use this URL
         val url = getString(R.string.remove_account_url)
         Timber.i("Loading '$url'")
-        webView.loadUrl(url)
+        webViewLayout.loadUrl(url)
 
         view.findViewById<MaterialToolbar?>(R.id.toolbar)?.apply {
             title = getString(R.string.remove_account)

AnkiDroid/src/main/java/com/ichi2/anki/pages/Statistics.kt

@@ -46,7 +46,6 @@ class Statistics :
         savedInstanceState: Bundle?,
     ) {
         super.onViewCreated(view, savedInstanceState)
-        webView.isNestedScrollingEnabled = true
 
         binding.deckName.setOnClickListener { startDeckSelection(all = false, filtered = false) }
         binding.appBar
@@ -79,7 +78,7 @@ class Statistics :
         val printManager = getSystemService(requireContext(), PrintManager::class.java)
         val currentDateTime = getTimestamp(TimeManager.time)
         val jobName = "${getString(R.string.app_name)}-stats-$currentDateTime"
-        val printAdapter = webView.createPrintDocumentAdapter(jobName)
+        val printAdapter = webViewLayout.createPrintDocumentAdapter(jobName)
         printManager?.print(
             jobName,
             printAdapter,
@@ -114,7 +113,7 @@ class Statistics :
             textBox.dispatchEvent(new Event("input", { bubbles: true }));
             textBox.dispatchEvent(new Event("change"));
             """.trimIndent()
-        webView.evaluateJavascript(javascriptCode, null)
+        webViewLayout.evaluateJavascript(javascriptCode, null)
     }
 
     companion object {

AnkiDroid/src/main/java/com/ichi2/anki/workarounds/NestedScrollingWebView.kt

@@ -191,3 +191,14 @@ class NestedScrollingWebView
             velocityY: Float,
         ) = childHelper.dispatchNestedPreFling(velocityX, velocityY)
     }
+
+class NestedScrollingSafeWebViewLayout : SafeWebViewLayout {
+    constructor(context: Context) : this(context, null)
+    constructor(context: Context, attrs: AttributeSet?) : this(context, attrs, 0)
+    constructor(context: Context, attrs: AttributeSet?, defStyleAttr: Int) : super(context, attrs, defStyleAttr)
+
+    override fun createWebView(): NestedScrollingWebView =
+        NestedScrollingWebView(context).also {
+            it.isNestedScrollingEnabled = true
+        }
+}

AnkiDroid/src/main/java/com/ichi2/anki/workarounds/SafeWebViewLayout.kt

@@ -28,7 +28,7 @@ import androidx.fragment.app.findFragment
 import com.ichi2.anki.BuildConfig
 import timber.log.Timber
 
-class SafeWebViewLayout :
+open class SafeWebViewLayout :
     FrameLayout,
     OnRenderProcessGoneListener {
     constructor(context: Context) : this(context, null)
@@ -43,7 +43,7 @@ class SafeWebViewLayout :
             field = value
         }
 
-    private fun createWebView() = WebView(context)
+    protected open fun createWebView() = WebView(context)
 
     init {
         addView(webView, webViewLayoutParams)
@@ -99,6 +99,8 @@ class SafeWebViewLayout :
 
     fun destroy() = webView.destroy()
 
+    fun createPrintDocumentAdapter(documentName: String) = webView.createPrintDocumentAdapter(documentName)
+
     override fun setOnScrollChangeListener(l: OnScrollChangeListener?) = webView.setOnScrollChangeListener(l)
 
     override fun onRenderProcessGone(webView: WebView) {

AnkiDroid/src/main/res/layout/image_occlusion.xml

@@ -27,7 +27,7 @@
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
         app:layout_constraintTop_toTopOf="parent"
-        app:layout_constraintBottom_toTopOf="@id/webview">
+        app:layout_constraintBottom_toTopOf="@id/webview_layout">
 
         <com.google.android.material.appbar.MaterialToolbar
             android:id="@+id/toolbar"
@@ -50,8 +50,8 @@
         </com.google.android.material.appbar.MaterialToolbar>
     </com.google.android.material.appbar.AppBarLayout>
 
-    <WebView
-        android:id="@+id/webview"
+    <com.ichi2.anki.workarounds.SafeWebViewLayout
+        android:id="@+id/webview_layout"
         android:layout_width="match_parent"
         android:layout_height="0dp"
         app:layout_constraintTop_toBottomOf="@id/app_bar"