It's definitely more noticable on Mac, where the print preview dialog may only partially cover the content.

We've had this problem for a long time. This may be the same as  bug 538468 ?

Bisected to https://chromium.googlesource.com/chromium/src/+log/acfb4199abf841a1577c3968579c43b0232a53b7..74335ef1219dd2178a5e754e4c4d2ea160eae3c9 so it's probably due to r314742 somehow. Maybe that'll give up a clue how to fix it? The PDF plugin has already moved from in-process PPAPI to out-of-process PPAPI before the regression.

In particular, the chrome/browser/resources/pdf/index.css change is what's triggering it. Possibly because print preview triggers a WebView resize?

 Issue 538468  has been merged into this issue.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/78b3a2e7c127d337bfc75a3668c74aeea38fdd14

commit 78b3a2e7c127d337bfc75a3668c74aeea38fdd14
Author: rbpotter <rbpotter@chromium.org>
Date: Thu Aug 17 01:08:40 2017

Fix PDF flicker in background of Print Preview

The source PDF flickers in the top left corner of the page behind
Print Preview any time the preview is regenerated. Fix this by not
resizing the PDF's frame in PrintRenderFrameHelper.

Bug:  739973 
Change-Id: I5431d291c9c0f65a50a425867cf66295b6225096
Reviewed-on: https://chromium-review.googlesource.com/612627
Commit-Queue: Rebekah Potter <rbpotter@chromium.org>
Reviewed-by: Lei Zhang <thestig@chromium.org>
Cr-Commit-Position: refs/heads/master@{#495028}
[modify] https://crrev.com/78b3a2e7c127d337bfc75a3668c74aeea38fdd14/components/printing/renderer/print_render_frame_helper.cc

 Issue 749448  has been merged into this issue.

Carrying over the M-61 label from  bug 749448 .

verified this on Mac 10.12.6/Ubuntu 14.04 (#62.0.3192.0) / Win 10 (#62.0.3191.0) and didn't observe any flashes while selecting the print range. Hence adding TE-Verified labels.

Attaching the screen-cast for reference.

 

Deleted: 739973.mp4 2.3 MB

	739973.mp4 2.3 MB View Download