LibWeb: Remove old FIXMEs about not setting up the navigation API's NHEs

Userland/Libraries/LibWeb/HTML/Navigation.cpp

@@ -116,10 +116,8 @@ JS::GCPtr<NavigationHistoryEntry> Navigation::current_entry() const
     if (has_entries_and_events_disabled())
         return nullptr;
 
-    // FIXME 2. Assert: navigation's current entry index is not −1.
-    // FIXME: This should not happen once Navigable's algorithms properly set up NHEs.
-    if (m_current_entry_index == -1)
-        return nullptr;
+    // 2. Assert: navigation's current entry index is not −1.
+    VERIFY(m_current_entry_index != -1);
 
     // 3. Return navigation's entry list[navigation's current entry index].
     return m_entry_list[m_current_entry_index];
@@ -162,10 +160,8 @@ bool Navigation::can_go_back() const
     if (has_entries_and_events_disabled())
         return false;
 
-    // FIXME 2. Assert: navigation's current entry index is not −1.
-    // FIXME: This should not happen once Navigable's algorithms properly set up NHEs.
-    if (m_current_entry_index == -1)
-        return false;
+    // 2. Assert: navigation's current entry index is not −1.
+    VERIFY(m_current_entry_index != -1);
 
     // 3. If this's current entry index is 0, then return false.
     // 4. Return true.
@@ -181,10 +177,8 @@ bool Navigation::can_go_forward() const
     if (has_entries_and_events_disabled())
         return false;
 
-    // FIXME 2. Assert: navigation's current entry index is not −1.
-    // FIXME: This should not happen once Navigable's algorithms properly set up NHEs.
-    if (m_current_entry_index == -1)
-        return false;
+    // 2. Assert: navigation's current entry index is not −1.
+    VERIFY(m_current_entry_index != -1);
 
     // 3. If this's current entry index is equal to this's entry list's size, then return false.
     // 4. Return true.