GitLab

Create LoginButton class as a base class for touch targets to enable
ripple effects.
This CL adds ripple to the following touch targets:
1. Dropdown menu button.
2. Submit button.
3. Pin keyboard button.

Bug: 778740
Change-Id: Ifd856da4ada342d94511fd2ead11933468fa8750
Reviewed-on: https://chromium-review.googlesource.com/739960
Commit-Queue: Xiaoyin Hu <xiaoyinh@chromium.org>
Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Reviewed-by: Jacob Dufault <jdufault@chromium.org>
Cr-Commit-Position: refs/heads/master@{#512572}