Sample Patch.

chrome/browser/resources/pdf/navigator.js

Index: chrome/browser/resources/pdf/navigator.js
diff --git a/chrome/browser/resources/pdf/navigator.js b/chrome/browser/resources/pdf/navigator.js
index 57c15d4d26c47c983f83a839c766cb79d22f9dfe..48a89be0ea4b59ac241c7eba067bb779be29a8e7 100644
--- a/chrome/browser/resources/pdf/navigator.js
+++ b/chrome/browser/resources/pdf/navigator.js
@@ -74,12 +74,14 @@ Navigator.prototype = {
     if (newTab) {
       this.navigateInNewTabCallback_(url);
     } else {
-      var pageNumber =
-          this.paramsParser_.getViewportFromUrlParams(url).page;
-      if (pageNumber != undefined)
-        this.viewport_.goToPage(pageNumber);
-      else
-        this.navigateInCurrentTabCallback_(url);
+      this.paramsParser_.getViewportFromUrlParams(
+          url, function(initialViewport) {
+        var pageNumber = initialViewport.pageNumber;
+        if (pageNumber != undefined)
+          this.viewport_.goToPage(pageNumber);
+        else
+          this.navigateInCurrentTabCallback_(url);
+      }.bind(this));
     }
   }
 };