Using the per-revision bisect providing the bisect results,
Good Build -- 57.0.2964.0 (revision : 440723)
Bad Build  -- 57.0.2965.0 (revision : 440816)

You are probably looking for a change made after 440784 (known good), but no later than 440785 (first known bad).
CHANGELOG URL:
  https://chromium.googlesource.com/chromium/src/+log/59ec2c1b938fc633a64079b176283b800d96f689..26b1599ba3f24f4124d8d78227fb815dc1c2e696

@stevenjb -- Could you please look into the issue, kindly re-assign if this is not related to your changes.
Thank You.

Will fix this for 59.

btw, the appearance of the ripple is already fixed in RTL (https://codereview.chromium.org/2719213002/)

This seems like something we may want to fix in paper-slider. It does not currently appear to support RTL:
https://github.com/Polymer/paper-slider/issues/22

hcarmona@, dbeam@ - thoughts?

Any updates on this? If it's not a launch-blocker, let's move it to Pri-2.

Hector is cool with me taking this, fyi on the owner change.

Making some notes because I need to switch to a higher priority issue:

This can be hack-fixed in paper-slider-extracted.js by reversing the values in _trackX. Though I'm not sure that's the right fix yet.

I've started looking at reversing the values in iron-range-behavior-extracted.js instead. That behavior is used in the sliders and progress bars. The progress elements are also not switching in RTL. (So this may be a better location to make the change since it can help both elements).

The progress bars could also be reversed easily in CSS using transform scale x -1. That doesn't work great for the slider though, since the item is interactive (mirroring the image kinda fails when interacting with, rather than just looking at the element).

There is a possible fix at CL https://codereview.chromium.org/2796903004/

I say possible fix because while that works, I'm looking for something better. The initial patch handles the RTL/LTR in the settings_slider.js. It would be nicer if the RTL handling were done at a lower level, such as within paper-slider.*.

An alternate fix (that changes paper-slider in Polymer) is at https://codereview.chromium.org/2800953002/

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/6a6df4ec7e64dfc890c6450cd4a86e39f6754da1

commit 6a6df4ec7e64dfc890c6450cd4a86e39f6754da1
Author: dschuyler <dschuyler@chromium.org>
Date: Fri Apr 07 19:17:09 2017

[Polymer] update paper-slider for RTL support

This CL applies a pull request submitted to Polymer to add RTL support
for paper-sliders.

BUG= 696437 
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:closure_compilation

Review-Url: https://codereview.chromium.org/2801193002
Cr-Commit-Position: refs/heads/master@{#462953}

[modify] https://crrev.com/6a6df4ec7e64dfc890c6450cd4a86e39f6754da1/third_party/polymer/v1_0/bower.json
[modify] https://crrev.com/6a6df4ec7e64dfc890c6450cd4a86e39f6754da1/third_party/polymer/v1_0/components-chromium/paper-slider/bower.json
[modify] https://crrev.com/6a6df4ec7e64dfc890c6450cd4a86e39f6754da1/third_party/polymer/v1_0/components-chromium/paper-slider/paper-slider-extracted.js
[modify] https://crrev.com/6a6df4ec7e64dfc890c6450cd4a86e39f6754da1/third_party/polymer/v1_0/components-chromium/paper-slider/paper-slider.html
[modify] https://crrev.com/6a6df4ec7e64dfc890c6450cd4a86e39f6754da1/third_party/polymer/v1_0/components_summary.txt
[modify] https://crrev.com/6a6df4ec7e64dfc890c6450cd4a86e39f6754da1/third_party/web-animations-js/sources/.bower.json

Verified this issue on Windows-10 and Ubuntu 14.04 using chrome latest Dev #59.0.3067.0 by following steps mentioned in the original comment, Observed the font size gets decreases if the slider is dragged towards tiny and increased when slider is dragged towards huge.

Tested the same on Mac OS 10.12.4, After step-1 observed the tabs are not displayed right to left instead it displays by default left to right. Due to this issue unable to drag the slider and verify this issue it from chrome-TE end. 

dschuyler@ Attaching scree-cast for reference could you please let us know is this is a known issue or do we need to file a separate one on this?

Thanks! 

Deleted: 696437.mp4 1.2 MB

	696437.mp4 1.2 MB View Download

brajkumar@: don't use that flag, actually change your language to Hebrew or Arabic in system settings