Auto merge of #12289 - nox:slate, r=Ms2ger

Properly check storage size against QUOTA_SIZE_LIMIT (fixes #12247)

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components/net/storage_thread.rs

@@ -144,12 +144,15 @@ impl StorageManager {
                 value: String) {
         let origin = self.origin_as_string(url);
 
-        let current_total_size = {
+        let (this_storage_size, other_storage_size) = {
             let local_data = self.select_data(StorageType::Local);
             let session_data = self.select_data(StorageType::Session);
             let local_data_size = local_data.get(&origin).map_or(0, |&(total, _)| total);
             let session_data_size = session_data.get(&origin).map_or(0, |&(total, _)| total);
-            local_data_size + session_data_size
+            match storage_type {
+                StorageType::Local => (local_data_size, session_data_size),
+                StorageType::Session => (session_data_size, local_data_size),
+            }
         };
 
         let data = self.select_data_mut(storage_type);
@@ -158,14 +161,14 @@ impl StorageManager {
         }
 
         let message = data.get_mut(&origin).map(|&mut (ref mut total, ref mut entry)| {
-            let mut new_total_size = current_total_size + value.as_bytes().len();
+            let mut new_total_size = this_storage_size + value.as_bytes().len();
             if let Some(old_value) = entry.get(&name) {
                 new_total_size -= old_value.as_bytes().len();
             } else {
                 new_total_size += name.as_bytes().len();
             }
 
-            if new_total_size > QUOTA_SIZE_LIMIT {
+            if (new_total_size + other_storage_size) > QUOTA_SIZE_LIMIT {
                 return Err(());
             }