Added new implementations for virtual containers

runtime/observatory/lib/src/elements/css/shared.css

Index: runtime/observatory/lib/src/elements/css/shared.css
diff --git a/runtime/observatory/lib/src/elements/css/shared.css b/runtime/observatory/lib/src/elements/css/shared.css
index 1f32ad40886a5c1a0a113be0faa24413cf6403f4..45c28ffe5b14b16a595cc6410201d02f5ffe0fcc 100644
--- a/runtime/observatory/lib/src/elements/css/shared.css
+++ b/runtime/observatory/lib/src/elements/css/shared.css
@@ -477,6 +477,34 @@ view-footer > a {
   display: block;
 }
 
+/* virtual-collection */
+
+virtual-collection {
+  display: block;
+  overflow-y: scroll;
+  width: 100%;
+  height: 100%;
+}
+
+virtual-collection .scroller {
+  position: relative;
+  overflow: hidden;
+  background: transparent;
+}
+
+virtual-collection .shifter {
+  background: transparent;
+  position: absolute;
+  top: 0;
+  left: 0;
+  right: 0;
+}
+
+virtual-collection .shifter > * {
+  position: relative;
+  top: -25%;
+}
+
 /* vm-connect-target */
 
 vm-connect-target > button.delete-button {