print_preview: Workaround of focus-scroll issue.

chrome/browser/resources/print_preview/previewarea/margin_control.js

Index: chrome/browser/resources/print_preview/previewarea/margin_control.js
diff --git a/chrome/browser/resources/print_preview/previewarea/margin_control.js b/chrome/browser/resources/print_preview/previewarea/margin_control.js
index 7ec2527e7a17e02389387adba3c9c806b7ec8b3d..5e5fa48d398ac438c2ac251da2467cec0610077b 100644
--- a/chrome/browser/resources/print_preview/previewarea/margin_control.js
+++ b/chrome/browser/resources/print_preview/previewarea/margin_control.js
@@ -349,6 +349,17 @@ cr.define('print_preview', function() {
      */
     setIsFocused_: function(isFocused) {
       this.isFocused_ = isFocused;
+      // TODO(tkent): This is a workaround of a preview-area scrolling
+      // issue. Blink scrolls preview-area on focus, but we don't want it.  We
+      // should adjust scroll position of PDF preview and positions of
+      // MarginContgrols here, or restructure the HTML so that the PDF review
+      // and MarginControls are on the single scrollable container.
+      // crbug.com/601341
+      if (isFocused) {
+        var previewArea = $('preview-area');
+        previewArea.scrollTop = 0;
+        previewArea.scrollLeft = 0;
+      }
     },
 
     /**
@@ -380,6 +391,7 @@ cr.define('print_preview', function() {
       var elStyle = window.getComputedStyle(this.getElement());
       var opacity = parseInt(elStyle.getPropertyValue('opacity'), 10);

[dpapad, 2016/04/29 17:59:13]

Nit: Instead of comparing opacity to 0 twice, how about the following

var disabled = parseInt(elStyle.getPropertyValue('opacity'), 10) == 0;
this.textbox_.setAttribute('aria-hidden', disabled);
this.textbox_.disabled = disabled;

[tkent, 2016/05/02 08:05:19]

Done.

       this.textbox_.setAttribute('aria-hidden', opacity == 0);
+      this.textbox_.disabled = opacity == 0;
     },
 
     /**