Auto merge of #17685 - paulrouget:rm_InitializeCompositing, r=jdm

remove no-op InitializeCompositing message

I think this is no-op.

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components/compositing/compositor.rs

@@ -742,10 +742,6 @@ impl<Window: WindowMethods> IOCompositor<Window> {
                 self.composite();
             }
 
-            WindowEvent::InitializeCompositing => {
-                self.initialize_compositing();
-            }
-
             WindowEvent::Resize(size) => {
                 self.on_resize_window_event(size);
             }
@@ -1566,9 +1562,6 @@ impl<Window: WindowMethods> IOCompositor<Window> {
         }
     }
 
-    fn initialize_compositing(&mut self) {
-    }
-
     fn get_root_pipeline_id(&self) -> Option<PipelineId> {
         self.root_pipeline.as_ref().map(|pipeline| pipeline.id)
     }