add debug menu entry for crashing WebView

This will be useful for making the app gracefully handle WebView
crashes.

Author: thestinger

app/src/main/java/app/grapheneos/pdfviewer/PdfViewer.java

@@ -684,6 +684,7 @@ public boolean onPrepareOptionsMenu(@NonNull Menu menu) {
                 R.id.action_outline));
         if (BuildConfig.DEBUG) {
             ids.add(R.id.debug_action_toggle_text_layer_visibility);
+            ids.add(R.id.debug_action_crash_webview);
         }
         if (mDocumentState < STATE_LOADED) {
             for (final int id : ids) {
@@ -764,6 +765,9 @@ public boolean onOptionsItemSelected(MenuItem item) {
         } else if (itemId == R.id.debug_action_toggle_text_layer_visibility) {
             binding.webview.evaluateJavascript("toggleTextLayerVisibility()", null);
             return true;
+        } else if (itemId == R.id.debug_action_crash_webview) {
+            binding.webview.loadUrl("chrome://crash");
+            return true;
         }
 
         return super.onOptionsItemSelected(item);

app/src/main/res/menu/pdf_viewer_debug.xml

@@ -7,4 +7,9 @@
         android:title="@string/debug_action_toggle_text_layer_visibility"
         app:showAsAction="never" />
 
+    <item
+        android:id="@+id/debug_action_crash_webview"
+        android:title="@string/debug_action_crash_webview"
+        app:showAsAction="never" />
+
 </menu>

app/src/main/res/values/strings.xml

@@ -20,6 +20,7 @@
     <string name="outline_not_available">No outline available</string>
 
     <string name="debug_action_toggle_text_layer_visibility">Toggle text layer visibility</string>
+    <string name="debug_action_crash_webview">Crash WebView</string>
 
     <string name="document_properties_invalid_date">Invalid date</string>
     <string name="document_properties_retrieval_failed">Failed to obtain document metadata</string>