Auto merge of #27417 - jdm:clear-reload, r=Manishearth

Make reload button clear the network cache.

The developer workflow in FxR is frustrating right now because of bugs like https://github.com/servo/servo/issues/24385. To allow us to put out a new release soon that addresses this papercut, these changes make the reload button clear the network cache in FxR.

---
- [x] `./mach build -d` does not report any errors
- [x] `./mach test-tidy` does not report any errors
- [x] These changes fix (kind of) #26411.
- [x] These changes do not require tests because can't test FxR.

ports/libsimpleservo/api/src/lib.rs

@@ -355,6 +355,13 @@ impl ServoGlue {
             })
     }
 
+    /// Reload the page.
+    pub fn clear_cache(&mut self) -> Result<(), &'static str> {
+        info!("clear_cache");
+        let event = WindowEvent::ClearCache;
+        self.process_event(event)
+    }
+
     /// Reload the page.
     pub fn reload(&mut self) -> Result<(), &'static str> {
         info!("reload");