OOP PDF: Fix incorrect scrolling during fit-to-page

chrome/test/data/pdf/test_util.js

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Utilities that are used in multiple tests.
 function MockWindow(width, height, sizer) {
   this.innerWidth = width;
   this.innerHeight = height;
   this.addEventListener = function(e, f) {
     if (e == 'scroll')
       this.scrollCallback = f;
     if (e == 'resize')
       this.resizeCallback = f;
   };
+  this.setSize = function(width, height) {
+    this.innerWidth = width;
+    this.innerHeight = height;
+    this.resizeCallback();
+  }
   this.scrollTo = function(x, y) {
     if (sizer) {
       x = Math.min(x, parseInt(sizer.style.width) - width);
       y = Math.min(y, parseInt(sizer.style.height) - height);
     }
     this.pageXOffset = Math.max(0, x);
     this.pageYOffset = Math.max(0, y);
     this.scrollCallback();
   };
   if (sizer) {
@@ skipping 55 matching lines @@
       width: w,
       height: h
     });
   };
   this.reset = function() {
     this.width = 0;
     this.height = 0;
     this.pageDimensions = [];
   };
 }