Still reproduces in 70.0.3514.0 (Official Build) dev (64-bit) (cohort: Dev)
Win 10

Does not apply to Chrome OS, different UI (no download bar)

The separator is actually to spec. It's not text and each download has an icon to separate it as well, so I don't think it's critical to increase its contrast.

The other icons are also... technically... to spec. But this is a place the spec doesn't seem to handle well. We decided to update the text color (which the icon color is derived from) to Grey 800. This has the following knock-on effects:
* The status text ("x/y GB, z secs left") is now #66696C (darker)
* The icon color is now #76797B, which is a ratio of 4.38... slightly under the minimum. Since it's not text, it should be okay.
* The bookmark bar color is now Grey 800 too. It's linked to the downloads color through the theme system.

Screenshots attached.

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Deleted: bookmark-bar-text-darker.PNG 16.3 KB

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LGTM

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/02dec75001f49d7ccfadce1f30602414a3d248d6

commit 02dec75001f49d7ccfadce1f30602414a3d248d6
Author: Bret Sepulveda <bsep@chromium.org>
Date: Tue Oct 09 22:19:56 2018

Update find bar, disabled icon, and download shelf colors for Refresh.

This patch makes the following changes:
* Disabled vector icon buttons now use kDisabledControlAlpha to derive
  their color (was a hardcoded value).
* Find bar text are icons are now Grey 900 (was black). The secondary
  match label is now Grey 700 (was much lighter) which brings it above
  a11y minimums.
* Download shelf text and bookmark bar text is now Grey 800 (was Grey
  700). This results in the download status text and icons being non-
  spec colors, though they are now darker and thus should also meet
  a11y minimums.

Screenshots are available in the associated bugs.

This patch also refactors the download shelf logic intended to update
colors when the View is added to a Widget into AddedToWidget instead
of ViewHierarchyChanged, so that it will only run once.

Bug:  872817 ,  870539 
Change-Id: I4a402a78c48be3cbb9310411f49e80f01d45451a
Reviewed-on: https://chromium-review.googlesource.com/c/1255891
Reviewed-by: Evan Stade <estade@chromium.org>
Reviewed-by: Michael Wasserman <msw@chromium.org>
Commit-Queue: Bret Sepulveda <bsep@chromium.org>
Cr-Commit-Position: refs/heads/master@{#598108}
[modify] https://crrev.com/02dec75001f49d7ccfadce1f30602414a3d248d6/chrome/browser/themes/theme_properties.cc
[modify] https://crrev.com/02dec75001f49d7ccfadce1f30602414a3d248d6/chrome/browser/ui/views/download/download_item_view.cc
[modify] https://crrev.com/02dec75001f49d7ccfadce1f30602414a3d248d6/chrome/browser/ui/views/download/download_item_view.h
[modify] https://crrev.com/02dec75001f49d7ccfadce1f30602414a3d248d6/chrome/browser/ui/views/download/download_shelf_view.cc
[modify] https://crrev.com/02dec75001f49d7ccfadce1f30602414a3d248d6/chrome/browser/ui/views/download/download_shelf_view.h
[modify] https://crrev.com/02dec75001f49d7ccfadce1f30602414a3d248d6/chrome/browser/ui/views/find_bar_view.cc
[modify] https://crrev.com/02dec75001f49d7ccfadce1f30602414a3d248d6/ui/native_theme/common_theme.cc
[modify] https://crrev.com/02dec75001f49d7ccfadce1f30602414a3d248d6/ui/views/controls/button/image_button_factory.cc

Verified the fix on Windows-10 using Chrome version #71.0.3577.0 as per the comment #0.
Attaching screen shot for reference.
Observed that download bar UI elements are not having low contrast.
Hence, the fix is working as expected. 
Adding the verified labels.
Note: Able to reproduce the issue on win-10 using chrome build with out fix.

Thanks...!!

Deleted: 870539.png 9.9 KB

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