constellation: Rename messages sent to the Constellation (#36341)

Messages that are sent to the `Constellation` have pretty ambiguous
names.
This change does two renames:

- `ConstellationMsg` → `EmbedderToConstellationMessage`
- `ScriptMsg` → `ScriptToConstellationMessage`

This naming reflects that the `Constellation` stands in between the
embedding layer and the script layer and can receive messages from both.
Soon both of these message types will live in `constellation_traits`,
reflecting the idea that the `_traits` variant for a crate is
responsible for exposing the API for that crate.

Testing: No new tests are necessary here as this just renames two enums.

Signed-off-by: Martin Robinson <mrobinson@igalia.com>

Signed-off-by: Martin Robinson <mrobinson@igalia.com>

components/script/clipboard_provider.rs

@@ -5,7 +5,7 @@
 use base::id::WebViewId;
 use embedder_traits::EmbedderMsg;
 use ipc_channel::ipc::channel;
-use script_traits::{ScriptMsg, ScriptToConstellationChan};
+use script_traits::{ScriptToConstellationChan, ScriptToConstellationMessage};
 
 /// A trait which abstracts access to the embedder's clipboard in order to allow unit
 /// testing clipboard-dependent parts of `script`.
@@ -25,19 +25,17 @@ impl ClipboardProvider for EmbedderClipboardProvider {
     fn get_text(&mut self) -> Result<String, String> {
         let (tx, rx) = channel().unwrap();
         self.constellation_sender
-            .send(ScriptMsg::ForwardToEmbedder(EmbedderMsg::GetClipboardText(
-                self.webview_id,
-                tx,
-            )))
+            .send(ScriptToConstellationMessage::ForwardToEmbedder(
+                EmbedderMsg::GetClipboardText(self.webview_id, tx),
+            ))
             .unwrap();
         rx.recv().unwrap()
     }
     fn set_text(&mut self, s: String) {
         self.constellation_sender
-            .send(ScriptMsg::ForwardToEmbedder(EmbedderMsg::SetClipboardText(
-                self.webview_id,
-                s,
-            )))
+            .send(ScriptToConstellationMessage::ForwardToEmbedder(
+                EmbedderMsg::SetClipboardText(self.webview_id, s),
+            ))
             .unwrap();
     }
 }