Prevent searching from breaking when opening a new file in the web viewer

web/pdf_find_controller.js

@@ -87,6 +87,12 @@ var PDFFindController = {
     }
   },
 
+  reset: function pdfFindControllerReset() {
+    this.startedTextExtraction = false;
+    this.extractTextPromises = [];
+    this.active = false;
+  },
+
   calcFindMatch: function(pageIndex) {
     var pageContent = this.pageContents[pageIndex];
     var query = this.state.query;

web/viewer.js

@@ -827,6 +827,8 @@ var PDFView = {
       };
     }
 
+    PDFFindController.reset();
+
     this.pdfDocument = pdfDocument;
 
     var errorWrapper = document.getElementById('errorWrapper');