DevTools: make flame chart a web component.

Source/devtools/front_end/components/flameChart.css

 .flame-chart-main-pane {
     overflow: hidden;
 }
 
 .flame-chart-marker-highlight-element {
     position: absolute;
     top: 0;
     height: 20px;
     width: 4px;
     margin: 0 -2px;
@@ skipping 15 matching lines @@
     border-width: 2px;
     border-style: solid;
     background-color: rgba(56, 121, 217, 0.2);
 }
 
 .flame-chart-v-scroll {
     flex: 0 0 14px;
     overflow-x: hidden;
 }
 
-body.platform-mac .flame-chart-v-scroll {
+.platform-mac .flame-chart-v-scroll {
     position: absolute;
     width: 14px;
     top: 0;
     right: 0;
     bottom: 0;
 }
 
 .flame-chart-selection-overlay {
     position: absolute;
     z-index: 100;
     background-color: rgba(56, 121, 217, 0.3);
     border-color: rgb(16, 81, 177);
     border-width: 1px;
     border-style: solid;
     pointer-events:none;
 }
 
 .flame-chart-selection-overlay .time-span {
     white-space: nowrap;
 }
+
+.flame-chart-entry-info {
+    position: absolute;
+    bottom: 20px;
+    left: 20px;
+    height: 120px;
+    background-color: rgba(255, 255, 255, 0.7);
+    pointer-events: none;
+}