The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/5546f73f3ced553cd8ffed80c2adff796d44e9e7

commit 5546f73f3ced553cd8ffed80c2adff796d44e9e7
Author: Biao She <bshe@chromium.org>
Date: Wed Nov 08 03:04:16 2017

Introduce new button style in VR

With this CL, all buttons in our UI switched to new design.
The new button is now composed by two elements:
1. A rounded rect as background.
2. A vector icon as the foreground.
When hovered, both background and foregroud popup a little bit combined
with color change.

Bug:  780527 
Change-Id: I7e08410c0b0d4db51884849db919b1a3d959a793
Reviewed-on: https://chromium-review.googlesource.com/748817
Commit-Queue: Biao She <bshe@chromium.org>
Reviewed-by: Ian Vollick <vollick@chromium.org>
Reviewed-by: Christopher Grant <cjgrant@chromium.org>
Cr-Commit-Position: refs/heads/master@{#514725}
[modify] https://crrev.com/5546f73f3ced553cd8ffed80c2adff796d44e9e7/chrome/browser/vr/BUILD.gn
[modify] https://crrev.com/5546f73f3ced553cd8ffed80c2adff796d44e9e7/chrome/browser/vr/color_scheme.cc
[modify] https://crrev.com/5546f73f3ced553cd8ffed80c2adff796d44e9e7/chrome/browser/vr/color_scheme.h
[modify] https://crrev.com/5546f73f3ced553cd8ffed80c2adff796d44e9e7/chrome/browser/vr/elements/button.cc
[modify] https://crrev.com/5546f73f3ced553cd8ffed80c2adff796d44e9e7/chrome/browser/vr/elements/button.h
[delete] https://crrev.com/1817342cd2b04512fb55bd048d1361ac10ae1cbc/chrome/browser/vr/elements/button_texture.cc
[delete] https://crrev.com/1817342cd2b04512fb55bd048d1361ac10ae1cbc/chrome/browser/vr/elements/button_texture.h
[add] https://crrev.com/5546f73f3ced553cd8ffed80c2adff796d44e9e7/chrome/browser/vr/elements/button_unittest.cc
[modify] https://crrev.com/5546f73f3ced553cd8ffed80c2adff796d44e9e7/chrome/browser/vr/elements/ui_element.cc
[modify] https://crrev.com/5546f73f3ced553cd8ffed80c2adff796d44e9e7/chrome/browser/vr/elements/ui_element.h
[modify] https://crrev.com/5546f73f3ced553cd8ffed80c2adff796d44e9e7/chrome/browser/vr/elements/ui_element_unittest.cc
[modify] https://crrev.com/5546f73f3ced553cd8ffed80c2adff796d44e9e7/chrome/browser/vr/elements/vector_icon.cc
[modify] https://crrev.com/5546f73f3ced553cd8ffed80c2adff796d44e9e7/chrome/browser/vr/elements/vector_icon.h
[delete] https://crrev.com/1817342cd2b04512fb55bd048d1361ac10ae1cbc/chrome/browser/vr/elements/vector_icon_button_texture.cc
[delete] https://crrev.com/1817342cd2b04512fb55bd048d1361ac10ae1cbc/chrome/browser/vr/elements/vector_icon_button_texture.h
[delete] https://crrev.com/1817342cd2b04512fb55bd048d1361ac10ae1cbc/chrome/browser/vr/elements/vector_icon_button_texture_unittest.cc
[modify] https://crrev.com/5546f73f3ced553cd8ffed80c2adff796d44e9e7/chrome/browser/vr/ui_renderer_unittest.cc
[modify] https://crrev.com/5546f73f3ced553cd8ffed80c2adff796d44e9e7/chrome/browser/vr/ui_scene_manager.cc
[modify] https://crrev.com/5546f73f3ced553cd8ffed80c2adff796d44e9e7/chrome/browser/vr/ui_scene_manager_unittest.cc