Introduce a helper method, in PDFPageView, for dispatching "...layerrendered" events

Currently we repeat virtually the same, with the exception of the name, event dispatching code four times for the different viewer layers.

web/pdf_page_view.js

@@ -361,6 +361,14 @@ class PDFPageView {
     );
   }
 
+  #dispatchLayerRendered(name, error) {
+    this.eventBus.dispatch(name, {
+      source: this,
+      pageNumber: this.id,
+      error,
+    });
+  }
+
   async #renderAnnotationLayer() {
     let error = null;
     try {
@@ -369,11 +377,7 @@ class PDFPageView {
       console.error(`#renderAnnotationLayer: "${ex}".`);
       error = ex;
     } finally {
-      this.eventBus.dispatch("annotationlayerrendered", {
-        source: this,
-        pageNumber: this.id,
-        error,
-      });
+      this.#dispatchLayerRendered("annotationlayerrendered", error);
     }
   }
 
@@ -385,11 +389,7 @@ class PDFPageView {
       console.error(`#renderAnnotationEditorLayer: "${ex}".`);
       error = ex;
     } finally {
-      this.eventBus.dispatch("annotationeditorlayerrendered", {
-        source: this,
-        pageNumber: this.id,
-        error,
-      });
+      this.#dispatchLayerRendered("annotationeditorlayerrendered", error);
     }
   }
 
@@ -422,12 +422,7 @@ class PDFPageView {
         this.#addLayer(this.xfaLayer.div, "xfaLayer");
         this.l10n.resume();
       }
-
-      this.eventBus.dispatch("xfalayerrendered", {
-        source: this,
-        pageNumber: this.id,
-        error,
-      });
+      this.#dispatchLayerRendered("xfalayerrendered", error);
     }
   }
 
@@ -446,12 +441,7 @@ class PDFPageView {
       console.error(`#renderTextLayer: "${ex}".`);
       error = ex;
     }
-
-    this.eventBus.dispatch("textlayerrendered", {
-      source: this,
-      pageNumber: this.id,
-      error,
-    });
+    this.#dispatchLayerRendered("textlayerrendered", error);
 
     this.#renderStructTreeLayer();
   }