perf(tabs): release stale image and tab state

apps/weblibre/lib/features/geckoview/utils/image_helper.dart

@@ -42,6 +42,7 @@ Future<EquatableImage?> tryDecodeImage(
   int? targetWidth,
   int? targetHeight,
   bool allowUpscaling = true,
+  bool cacheResult = true,
 }) async {
   // The decode options are part of the identity of the result, not just of the
   // request: the same bytes decoded at a thumbnail's target width and at an
@@ -55,11 +56,13 @@ Future<EquatableImage?> tryDecodeImage(
     allowUpscaling: allowUpscaling,
   );
 
-  final cached = _cache.get(identity);
-  if (cached?.value != null) {
-    return cached;
-  } else if (cached != null) {
-    _cache.remove(identity);
+  if (cacheResult) {
+    final cached = _cache.get(identity);
+    if (cached?.value != null) {
+      return cached;
+    } else if (cached != null) {
+      _cache.remove(identity);
+    }
   }
 
   try {
@@ -74,7 +77,9 @@ Future<EquatableImage?> tryDecodeImage(
     final image = EquatableImage(frameInfo.image, identity: identity);
 
     if (image.value != null && image.value!.width > 0) {
-      _cache.set(identity, image);
+      if (cacheResult) {
+        _cache.set(identity, image);
+      }
       return image;
     }
   } catch (e, s) {
@@ -87,7 +92,9 @@ Future<EquatableImage?> tryDecodeImage(
           targetHeight: targetHeight,
         );
         if (svgImage != null) {
-          _cache.set(identity, svgImage);
+          if (cacheResult) {
+            _cache.set(identity, svgImage);
+          }
           return svgImage;
         }
       } catch (svgError, svgStackTrace) {