[DevTools] Migrate Popover to GlassPane

third_party/WebKit/Source/devtools/front_end/ui/popover.css

-:host {
-    position: absolute;
-    z-index: 600;
-    pointer-events: none;
-    display: flex;
-    background-color: white;
-    box-shadow: 0 6px 10px 0 rgba(0, 0, 0, 0.3), 0 2px 2px 0 rgba(0, 0, 0, 0.2), 0 1px 4px 0 rgba(0, 0, 0, 0.37);
-    border-radius: 2px;
-}
+/*
+ * Copyright 2017 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.
+ */
 
 .widget {
-    flex: auto;
-    pointer-events: none;
-    overflow: visible;
-}
-
-.popover-content {
-    pointer-events: auto;
+    display: flex;
+    background: white;
+    box-shadow: 0 0 0 1px rgba(0, 0, 0, 0.2), 0 2px 4px rgba(0, 0, 0, 0.2), 0 2px 6px rgba(0, 0, 0, 0.1);
+    border-radius: 2px;
     overflow: auto;
     -webkit-user-select: text;
     line-height: 11px;
-    flex: auto;
     padding: 6px;
 }
 
-.popover-content.no-padding {
+.widget.no-padding {
     padding: 0;
-    overflow: hidden;
 }
-
-.arrow {
-    position: absolute;
-    background-image: url(Images/popoverArrows.png);
-    width: 19px;
-    height: 19px;
-    margin-top: -19px;
-    top: 0;
-    left: 0;
-    z-index: 1;
-}
-
-:host-context(.-theme-with-dark-background) .arrow {
-    -webkit-filter: invert(80%);
-}
-
-.arrow.top-left-arrow {
-    /* The default is top-left, no styles needed. */
-}
-
-.arrow.top-right-arrow {
-    right: 19px;
-    left: auto;
-}
-
-.arrow.bottom-left-arrow {
-    top: auto;
-    bottom: 0;
-    margin-top: 0;
-    margin-bottom: -19px;
-    background-position: 0 -19px;
-}
-
-.arrow.bottom-right-arrow {
-    right: 15px;
-    left: auto;
-    top: auto;
-    bottom: 0;
-    margin-top: 0;
-    margin-bottom: -19px;
-    background-position: 0 -19px;
-}