Auto merge of #8886 - paulrouget:freeze-pipeline-iframe, r=mbrubeck,jdm

Freeze old pipeline in iframes

Fixes https://github.com/servo/servo/issues/8673 and part of https://github.com/servo/servo/issues/8674

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components/compositing/constellation.rs

@@ -834,6 +834,10 @@ impl<LTF: LayoutTaskFactory, STF: ScriptTaskFactory> Constellation<LTF, STF> {
             }
         };
 
+        if let Some(pipeline_id) = old_pipeline_id {
+            self.pipeline(pipeline_id).freeze();
+        }
+
         // Create the new pipeline, attached to the parent and push to pending frames
         let window_size = old_pipeline_id.and_then(|old_pipeline_id| {
             self.pipeline(old_pipeline_id).size

components/script/script_task.rs

@@ -135,6 +135,8 @@ struct InProgressLoad {
     layout_chan: LayoutChan,
     /// The current viewport clipping rectangle applying to this pipeline, if any.
     clip_rect: Option<Rect<f32>>,
+    /// Window is frozen (navigated away while loading for example).
+    is_frozen: bool,
     /// The requested URL of the load.
     url: Url,
 }
@@ -152,6 +154,7 @@ impl InProgressLoad {
             layout_chan: layout_chan,
             window_size: window_size,
             clip_rect: None,
+            is_frozen: false,
             url: url,
         }
     }
@@ -1319,31 +1322,38 @@ impl ScriptTask {
 
     /// Handles freeze message
     fn handle_freeze_msg(&self, id: PipelineId) {
-        // Workaround for a race condition when navigating before the initial page has
-        // been constructed c.f. https://github.com/servo/servo/issues/7677
-        if self.page.borrow().is_none() {
-            return
-        };
-        let page = self.root_page();
-        let page = page.find(id).expect("ScriptTask: received freeze msg for a
-                    pipeline ID not associated with this script task. This is a bug.");
-        let window = page.window();
-        window.freeze();
+        if let Some(root_page) = self.page.borrow().as_ref() {
+            if let Some(ref inner_page) = root_page.find(id) {
+                let window = inner_page.window();
+                window.freeze();
+                return;
+            }
+        }
+        let mut loads = self.incomplete_loads.borrow_mut();
+        if let Some(ref mut load) = loads.iter_mut().find(|load| load.pipeline_id == id) {
+            load.is_frozen = true;
+            return;
+        }
+        panic!("freeze sent to nonexistent pipeline");
     }
 
     /// Handles thaw message
     fn handle_thaw_msg(&self, id: PipelineId) {
-        // We should only get this message when moving in history, so all pages requested
-        // should exist.
-        let page = self.root_page().find(id).unwrap();
-
-        let needed_reflow = page.set_reflow_status(false);
-        if needed_reflow {
-            self.rebuild_and_force_reflow(&*page, ReflowReason::CachedPageNeededReflow);
+        if let Some(ref inner_page) = self.root_page().find(id) {
+            let needed_reflow = inner_page.set_reflow_status(false);
+            if needed_reflow {
+                self.rebuild_and_force_reflow(&*inner_page, ReflowReason::CachedPageNeededReflow);
+            }
+            let window = inner_page.window();
+            window.thaw();
+            return;
         }
-
-        let window = page.window();
-        window.thaw();
+        let mut loads = self.incomplete_loads.borrow_mut();
+        if let Some(ref mut load) = loads.iter_mut().find(|load| load.pipeline_id == id) {
+            load.is_frozen = false;
+            return;
+        }
+        panic!("thaw sent to nonexistent pipeline");
     }
 
     fn handle_focus_iframe_msg(&self,
@@ -1732,6 +1742,10 @@ impl ScriptTask {
             }
         }
 
+        if incomplete.is_frozen {
+            window.freeze();
+        }
+
         page_remover.neuter();
 
         document.get_current_parser().unwrap()

tests/wpt/mozilla/meta/MANIFEST.json

@@ -5679,6 +5679,12 @@
             "url": "/_mozilla/mozilla/load_event.html"
           }
         ],
+        "mozilla/mozbrowser/iframe_goback.html": [
+          {
+            "path": "mozilla/mozbrowser/iframe_goback.html",
+            "url": "/_mozilla/mozilla/mozbrowser/iframe_goback.html"
+          }
+        ],
         "mozilla/mozbrowser/mozbrowsericonchange_event.html": [
           {
             "path": "mozilla/mozbrowser/mozbrowsericonchange_event.html",

tests/wpt/mozilla/tests/mozilla/mozbrowser/iframe_goback.html

@@ -0,0 +1,37 @@
+<head>
+<title>iframe.goBack()</title>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+</head>
+<body>
+<script>
+
+async_test(function(t) {
+
+  var url2 = "data:,a";
+  var url1 = `data:text/html,<script>setTimeout(() => location.assign("${url2}"), 0)</${"script"}>`;
+
+  var locations = []
+  var expected_locations = [url1, url2, url1];
+
+  var iframe = document.createElement("iframe");
+  iframe.mozbrowser = "true";
+  iframe.src = url1;
+
+  iframe.addEventListener("mozbrowserlocationchange", e => {
+    locations.push(e.detail);
+    if (e.detail == url2) {
+      iframe.goBack();
+    }
+    if (locations.length == expected_locations.length) {
+       assert_array_equals(locations, expected_locations);
+       t.done();
+    }
+  });
+
+  document.body.appendChild(iframe);
+
+});
+
+</script>
+</body>