[profiler] This adds function butterflies to the function list.

tools/profview/profview.css

 table.calltree {
   width : 100%;
 }
 
 .numeric {
   width : 12ex;
 }
 
+.numeric-hidden {
+  display : none;
+}
+
 body {
   font-family: 'Roboto', sans-serif;
 }
 
 div.code-type-chip {
   display : inline-block;
   padding : 0.0em;
 }
 
 span.code-type-chip {
@@ skipping 25 matching lines @@
 }
 
 div.active-mode-button {
   background-color: #0000ff;
   box-shadow: 3px 3px 2px #a0a0ff;
 }
 
 div.active-mode-button:hover {
   background-color: #0000ff;
 }