Split MessageEditor in edit-specifics & reusable part for main composer

src/editor/model.js

@@ -24,9 +24,17 @@ export default class EditorModel {
         this._activePartIdx = null;
         this._autoComplete = null;
         this._autoCompletePartIdx = null;
+        this.setUpdateCallback(updateCallback);
+    }
+
+    setUpdateCallback(updateCallback) {
         this._updateCallback = updateCallback;
     }
 
+    get partCreator() {
+        return this._partCreator;
+    }
+
     clone() {
         return new EditorModel(this._parts, this._partCreator, this._updateCallback);
     }

src/editor/parts.js

@@ -325,7 +325,7 @@ class PillCandidatePart extends PlainPart {
     }
 
     createAutoComplete(updateCallback) {
-        return this._autoCompleteCreator(updateCallback);
+        return this._autoCompleteCreator.create(updateCallback);
     }
 
     acceptsInsertion(chr, i) {
@@ -363,10 +363,14 @@ export function autoCompleteCreator(getAutocompleterComponent, updateQuery) {
 }
 
 export class PartCreator {
-    constructor(autoCompleteCreator, room, client) {
+    constructor(room, client, autoCompleteCreator) {
         this._room = room;
         this._client = client;
-        this._autoCompleteCreator = autoCompleteCreator(this);
+        this._autoCompleteCreator = {create: autoCompleteCreator && autoCompleteCreator(this)};
+    }
+
+    setAutoCompleteCreator(autoCompleteCreator) {
+        this._autoCompleteCreator.create = autoCompleteCreator(this);
     }
 
     createPartForInput(input) {