diff --git a/web/app.js b/web/app.js
index 63e7142a2..62b65b157 100644
--- a/web/app.js
+++ b/web/app.js
@@ -346,25 +346,6 @@ let PDFViewerApplication = {
       linkService: pdfLinkService,
       eventBus,
     });
-    this.findController.onUpdateResultsCount = (matchesCount) => {
-      if (this.supportsIntegratedFind) {
-        this.externalServices.updateFindMatchesCount(matchesCount);
-      } else {
-        this.findBar.updateResultsCount(matchesCount);
-      }
-    };
-    this.findController.onUpdateState = (state, previous, matchesCount) => {
-      if (this.supportsIntegratedFind) {
-        this.externalServices.updateFindControlState({
-          result: state,
-          findPrevious: previous,
-          matchesCount,
-        });
-      } else {
-        this.findBar.updateUIState(state, previous, matchesCount);
-      }
-    };
-
     this.pdfViewer.setFindController(this.findController);
 
     // TODO: improve `PDFFindBar` constructor parameter passing
@@ -1343,6 +1324,8 @@ let PDFViewerApplication = {
     eventBus.on('documentproperties', webViewerDocumentProperties);
     eventBus.on('find', webViewerFind);
     eventBus.on('findfromurlhash', webViewerFindFromUrlHash);
+    eventBus.on('updatefindmatchescount', webViewerUpdateFindMatchesCount);
+    eventBus.on('updatefindcontrolstate', webViewerUpdateFindControlState);
     if (typeof PDFJSDev === 'undefined' || PDFJSDev.test('GENERIC')) {
       eventBus.on('fileinputchange', webViewerFileInputChange);
     }
@@ -1414,6 +1397,8 @@ let PDFViewerApplication = {
     eventBus.off('documentproperties', webViewerDocumentProperties);
     eventBus.off('find', webViewerFind);
     eventBus.off('findfromurlhash', webViewerFindFromUrlHash);
+    eventBus.off('updatefindmatchescount', webViewerUpdateFindMatchesCount);
+    eventBus.off('updatefindcontrolstate', webViewerUpdateFindControlState);
     if (typeof PDFJSDev === 'undefined' || PDFJSDev.test('GENERIC')) {
       eventBus.off('fileinputchange', webViewerFileInputChange);
     }
@@ -1976,6 +1961,26 @@ function webViewerFindFromUrlHash(evt) {
   });
 }
 
+function webViewerUpdateFindMatchesCount({ matchesCount, }) {
+  if (PDFViewerApplication.supportsIntegratedFind) {
+    PDFViewerApplication.externalServices.updateFindMatchesCount(matchesCount);
+  } else {
+    PDFViewerApplication.findBar.updateResultsCount(matchesCount);
+  }
+}
+
+function webViewerUpdateFindControlState({ state, previous, matchesCount, }) {
+  if (PDFViewerApplication.supportsIntegratedFind) {
+    PDFViewerApplication.externalServices.updateFindControlState({
+      result: state,
+      findPrevious: previous,
+      matchesCount,
+    });
+  } else {
+    PDFViewerApplication.findBar.updateUIState(state, previous, matchesCount);
+  }
+}
+
 function webViewerScaleChanging(evt) {
   PDFViewerApplication.toolbar.setPageScale(evt.presetValue, evt.scale);
 
diff --git a/web/pdf_find_controller.js b/web/pdf_find_controller.js
index 082eb6a63..a74df0893 100644
--- a/web/pdf_find_controller.js
+++ b/web/pdf_find_controller.js
@@ -57,9 +57,6 @@ class PDFFindController {
     this._linkService = linkService;
     this._eventBus = eventBus;
 
-    this.onUpdateResultsCount = null;
-    this.onUpdateState = null;
-
     this._reset();
 
     eventBus.on('findbarclose', () => {
@@ -564,19 +561,19 @@ class PDFFindController {
   }
 
   _updateUIResultsCount() {
-    if (!this.onUpdateResultsCount) {
-      return;
-    }
-    const matchesCount = this._requestMatchesCount();
-    this.onUpdateResultsCount(matchesCount);
+    this._eventBus.dispatch('updatefindmatchescount', {
+      source: this,
+      matchesCount: this._requestMatchesCount(),
+    });
   }
 
   _updateUIState(state, previous) {
-    if (!this.onUpdateState) {
-      return;
-    }
-    const matchesCount = this._requestMatchesCount();
-    this.onUpdateState(state, previous, matchesCount);
+    this._eventBus.dispatch('updatefindcontrolstate', {
+      source: this,
+      state,
+      previous,
+      matchesCount: this._requestMatchesCount(),
+    });
   }
 }