[ash-md] Updates web-ui tooltips to MD

ui/login/bubble.css

 /* Copyright 2014 The Chromium Authors. All rights reserved.
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  *
  * Css based bubble.
  */
 
 .bubble {
   -webkit-transition: opacity 200ms ease-in-out;
-  background: white;
-  border: 1px solid rgba(0, 0, 0, 0.25);
+  background: rgba(0, 0, 0, 0.8);
+  border-radius: 2px;
+  color: rgba(255, 255, 255, 0.87);
   box-shadow: 0 2px 4px rgba(0, 0, 0, 0.2);
   font-size: 12px;
   margin: 2px;
   max-width: 250px;
   padding: 16px;
   position: absolute;
 }
 
-.bubble::before {
-  border-style: solid;
-  border-width: 8px;
-  content: '';
-  display: block;
-  position: absolute;
-}
-
-.bubble-top::before {
-  border-color: rgba(0, 0, 0, 0.25) transparent transparent transparent;
-  bottom: -16px;
-}
-
-html[dir=ltr] .bubble-top::before {
-  left: 17px;
-}
-
-html[dir=rtl] .bubble-top::before {
-  right: 17px;
-}
-
-html[dir=ltr] .bubble-right::before,
-html[dir=rtl] .bubble-left::before {
-  border-color: transparent rgba(0, 0, 0, 0.25) transparent transparent;
-  left: -16px;
-  top: 17px;
-}
-
-.bubble-bottom::before {
-  border-color: transparent transparent rgba(0, 0, 0, 0.25) transparent;
-  top: -16px;
-}
-
-html[dir=ltr] .bubble-bottom::before {
-  left: 17px;
-}
-
-html[dir=rtl] .bubble-bottom::before {
-  right: 17px;
-}
-
-html[dir=ltr] .bubble-left::before,
-html[dir=rtl] .bubble-right::before {
-  border-color: transparent transparent transparent rgba(0, 0, 0, 0.25);
-  right: -16px;
-  top: 17px;
-}
-
-.bubble::after {
-  border-style: solid;
-  border-width: 8px;
-  content: '';
-  display: block;
-  position: absolute;
-}
-
-.bubble-top::after {
-  border-color: white transparent transparent transparent;
-  bottom: -15px;
-}
-
-html[dir=ltr] .bubble-top::after {
-  left: 17px;
-}
-
-html[dir=rtl] .bubble-top::after {
-  right: 17px;
-}
-
-html[dir=ltr] .bubble-right::after,
-html[dir=rtl] .bubble-left::after {
-  border-color: transparent white transparent transparent;
-  left: -15px;
-  top: 17px;
-}
-
-.bubble-bottom::after {
-  border-color: transparent transparent white transparent;
-  top: -15px;
-}
-
-html[dir=ltr] .bubble-bottom::after {
-  left: 17px;
-}
-
-html[dir=rtl] .bubble-bottom::after {
-  right: 17px;
-}
-
-html[dir=ltr] .bubble-left::after,
-html[dir=rtl] .bubble-right::after {
-  border-color: transparent transparent transparent white;
-  right: -15px;
-  top: 17px;
-}
-
 .error-message-bubble {
   -webkit-padding-start: 30px;
   background: url(chrome://theme/IDR_WARNING) left top no-repeat;
   background-size: 24px;
 }
 
 .error-message-bubble-padding {
   margin-bottom: 10px;
 }
 
 html[dir=rtl] .error-message-bubble {
   background-position: right top;
 }