Aggressively set the theme state on every chapter change

Affects: https://ebce-lyrasis.atlassian.net/browse/PP-1691

org.librarysimplified.r2.vanilla/src/main/java/org/librarysimplified/r2/vanilla/internal/SR2Controller.kt

@@ -688,7 +688,7 @@ internal class SR2Controller private constructor(
 
       this.logger.debug("Translated {} to {}", chapterURL, resolvedURL)
 
-      val future =
+      val openFuture =
         connection.openURL(resolvedURL.toString())
           .handle { _, exception ->
             if (exception != null) {
@@ -716,17 +716,28 @@ internal class SR2Controller private constructor(
        * If there's a fragment, attempt to scroll to it.
        */
 
-      when (val fragment = chapterURL.substringAfter('#', "")) {
-        "" -> future
-
-        else ->
-          future.thenCompose {
-            connection.executeJS { js -> js.scrollToId(fragment) }
-          }.handle { _, exception ->
-            if (exception != null) {
-              this.logger.debug("{} Failed to scroll to fragment ID: ", this.name(), exception)
+      val scrollFuture =
+        when (val fragment = chapterURL.substringAfter('#', "")) {
+          "" -> openFuture
+
+          else ->
+            openFuture.thenCompose {
+              connection.executeJS { js -> js.scrollToId(fragment) }
+            }.handle { _, exception ->
+              if (exception != null) {
+                this.logger.debug("{} Failed to scroll to fragment ID: ", this.name(), exception)
+              }
             }
-          }
+        }
+
+      /*
+       * Evidently, web views on more modern platforms will no longer preserve the theme state.
+       * We therefore need to set the theme information every time the chapter changes for
+       * any reason.
+       */
+
+      scrollFuture.thenCompose {
+        this.executeThemeSet(this.waitForWebViewAvailability(), this.themeNow())
       }
     } catch (e: Exception) {
       this.logger.error(

org.librarysimplified.r2.views/src/main/java/org/librarysimplified/r2/views/SR2ReaderFragment.kt

@@ -16,9 +16,6 @@ import androidx.core.view.MenuItemCompat
 import androidx.core.view.forEach
 import androidx.core.view.isVisible
 import io.reactivex.disposables.CompositeDisposable
-import org.librarysimplified.r2.api.SR2Bookmark
-import org.librarysimplified.r2.api.SR2Bookmark.Type.EXPLICIT
-import org.librarysimplified.r2.api.SR2ControllerType
 import org.librarysimplified.r2.api.SR2Event
 import org.librarysimplified.r2.api.SR2Event.SR2BookmarkEvent.SR2BookmarkCreated
 import org.librarysimplified.r2.api.SR2Event.SR2BookmarkEvent.SR2BookmarkDeleted
@@ -32,7 +29,6 @@ import org.librarysimplified.r2.api.SR2Event.SR2Error.SR2WebViewInaccessible
 import org.librarysimplified.r2.api.SR2Event.SR2OnCenterTapped
 import org.librarysimplified.r2.api.SR2Event.SR2ReadingPositionChanged
 import org.librarysimplified.r2.api.SR2Event.SR2ThemeChanged
-import org.librarysimplified.r2.api.SR2Locator
 import org.librarysimplified.r2.api.SR2ScrollingMode.SCROLLING_MODE_CONTINUOUS
 import org.librarysimplified.r2.api.SR2ScrollingMode.SCROLLING_MODE_PAGINATED
 import org.librarysimplified.r2.api.SR2Theme
@@ -297,21 +293,6 @@ class SR2ReaderFragment : SR2Fragment() {
     this.menuBookmarkItem.icon?.colorFilter = currentColorFilter
   }
 
-  private fun findBookmarkForCurrentPage(
-    controllerNow: SR2ControllerType,
-    currentPosition: SR2Locator,
-  ): SR2Bookmark? {
-    return controllerNow.bookmarksNow()
-      .find { bookmark -> this.locationMatchesBookmark(bookmark, currentPosition) }
-  }
-
-  private fun locationMatchesBookmark(
-    bookmark: SR2Bookmark,
-    location: SR2Locator,
-  ): Boolean {
-    return bookmark.type == EXPLICIT && location.compareTo(bookmark.locator) == 0
-  }
-
   private fun onControllerEvent(event: SR2Event) {
     SR2UIThread.checkIsUIThread()