Polish UI for Tab Grid

This is the CL for following UI polishment:

* Fade out title edge instead of ellipsizing it.
* Change the drawable for close tab in tab grid.
* Adjust padding in recyclerview.
* Adjust padding for incognito toggle indicator.
(TODO: Need a good way to adjust the width of indicator.)

Bug: 937537
Change-Id: Ic56d884a4fb83fa2390c628152cc8d5c94977689
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1538809
Commit-Queue: Yue Zhang <yuezhanggg@google.com>
Reviewed-by: Yusuf Ozuysal <yusufo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#644121}
3 files changed