Only trigger navigation in distiller if in print preview

components/dom_distiller/core/javascript/dom_distiller_viewer.js

 // Copyright 2014 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.
 
 // This variable will be changed by iOS scripts.
 var distiller_on_ios = false;
 
 function addToPage(html) {
   var div = document.createElement('div');
   div.innerHTML = html;
@@ skipping 25 matching lines @@
     parent.replaceChild(container, placeholders[i]);
   }
 }
 
 function showLoadingIndicator(isLastPage) {
   document.getElementById('loadingIndicator').className =
       isLastPage ? 'hidden' : 'visible';
   // This function will be one of the last things to occur when a page is
   // loaded. This is temporarily used to signal print preview to generate
   // a PDF.
-  if (isLastPage) {
+  if (isLastPage && typeof is_print_preview_distiller !== 'undefined'

[Bernhard Bauer, 2016/04/25 15:36:38]

If you declare this at the global level and initialize it to false, you don't
need this check. Also, the JS style guide doesn't seem to mention global
variables, so I think by default the same naming style applies, i.e.
lowerInitialCamelCase.

[mdjones, 2016/04/25 16:33:13]

Updated var name. Unfortunately I can't pre-define the isPrintPreviewDistiller
var because this script usually runs after it would be set in the c++ code.

[Bernhard Bauer, 2016/04/25 17:30:31]

But that's fine, because you'll have declared the variable beforehand at
top-level, no? Or is it that this whole file will be evaluated only later? That
would seem very strange to me.

[mdjones, 2016/04/25 18:24:08]

Yes, the whole file is parsed after the JavaScript is run. This behavior might
be the result of how we send content to the page and the fact that we are using
a custom scheme. Really this whole mechanism needs to be replaced by a proper
signal from the renderer, but I don't currently have the time to implement this
solution.

[Bernhard Bauer, 2016/04/28 16:24:04]

That does not seem like the right solution. From the context, it looks like you
are trying to fix a flaky test, so you would really do well to fix the order in
which things happen here (or find another way of doing it, like passing in the
flag to the URL that gets loaded?), otherwise you're just going to run into
similar issues later.

+      && is_print_preview_distiller) {
     setTimeout(function() {
         window.location = window.location + "#loaded";
     }, 0);
   }
 }
 
 // Sets the title.
 function setTitle(title) {
   var holder = document.getElementById('titleHolder');
 
@@ skipping 346 matching lines @@
       clampedScale = scaling;
       restoreCenter();
     }
   };
 }());
 
 window.addEventListener('touchstart', pincher.handleTouchStart, false);
 window.addEventListener('touchmove', pincher.handleTouchMove, false);
 window.addEventListener('touchend', pincher.handleTouchEnd, false);
 window.addEventListener('touchcancel', pincher.handleTouchCancel, false);