Version: 53 ToT
OS: Chrome OS
Cause of regression (confirmed with bisect): https://crrev.com/20e7d3f385060e0c2de2a86d5dcf81c4c0ca8c8f

Note: Marked as Proj-MaterialDesign-CrOS for tracking purposes, since the offending CL was a material design change. However, this regression is only seen when Ash material design is *not* enabled.

Steps to reproduce:
1. In an Ash desktop, switch the shelf orientation from bottom to left.
2. Switch the shelf orientation from left to right.

What happens:
The items in the system tray area (system tray, notifications button) are 6px from the right edge of the screen (including the 3px black bar containing the activity indicators). Clicking on one of these items will cause it to re-layout to be 9px from the right edge of the screen.

What should happen instead:
The items in the system tray area (system tray, notifications button) should be 9px from the right edge of the screen. Clicking on these items should not cause their layout to change.

Note: the bug also reproduces if you instead switch from bottom->right->left.