constellation blocks on compositor before sending permission to paint to renderers

2 files changed, 9 insertions, 4 deletions

diff --git a/src/components/main/compositing/mod.rs b/src/components/main/compositing/mod.rs
index b13c5cbc8d0..b45cbad2197 100644
--- a/src/components/main/compositing/mod.rs
+++ b/src/components/main/compositing/mod.rs
@@ -141,7 +141,7 @@ pub enum Msg {
     /// Alerts the compositor to the current status of rendering.
     ChangeRenderState(RenderState),
     /// Sets the channel to the current layout and render tasks, along with their id
-    SetIds(SendableFrameTree),
+    SetIds(SendableFrameTree, Chan<()>),
 }
 
 /// Azure surface wrapping to work with the layers infrastructure.
@@ -345,8 +345,9 @@ impl CompositorTask {
                     ChangeReadyState(ready_state) => window.set_ready_state(ready_state),
                     ChangeRenderState(render_state) => window.set_render_state(render_state),
 
-                    SetIds(frame_tree) => {
+                    SetIds(frame_tree, response_chan) => {
                         pipeline = Some(frame_tree.pipeline);
+                        response_chan.send(());
                     }
 
                     GetSize(chan) => {
diff --git a/src/components/main/constellation.rs b/src/components/main/constellation.rs
index 7c1c8a1fa50..4ffe5e3230d 100644
--- a/src/components/main/constellation.rs
+++ b/src/components/main/constellation.rs
@@ -514,10 +514,12 @@ impl Constellation {
                     // TODO(tkuehn): In fact, this kind of message might be provably
                     // impossible to occur.
                     if current_frame.contains(pipeline_id) {
+                        let (port, chan) = comm::stream();
+                        self.compositor_chan.send(SetIds(current_frame.to_sendable(), chan));
+                        port.recv();
                         for current_frame.iter().advance |frame| {
                             frame.pipeline.grant_paint_permission();
                         }
-                        self.compositor_chan.send(SetIds(current_frame.to_sendable()));
                         return true;
                     }
                 }
@@ -606,7 +608,9 @@ impl Constellation {
     // Grants a frame tree permission to paint; optionally updates navigation to reflect a new page
     fn grant_paint_permission(&mut self, frame_tree: @mut FrameTree) {
         // Give permission to paint to the new frame and all child frames
-        self.compositor_chan.send(SetIds(frame_tree.to_sendable()));
+        let (port, chan) = comm::stream();
+        self.compositor_chan.send(SetIds(frame_tree.to_sendable(), chan));
+        port.recv();
         for frame_tree.iter().advance |frame| {
             frame.pipeline.grant_paint_permission();
         }