DevTools: make flame chart a web component.

Source/devtools/front_end/flameChart.css

Index: Source/devtools/front_end/flameChart.css
diff --git a/Source/devtools/front_end/flameChart.css b/Source/devtools/front_end/flameChart.css
index c27f53051f88b587708fd5b042af5183f10000e4..f1800b79a3337bf20840dc8adac77be7f63696da 100644
--- a/Source/devtools/front_end/flameChart.css
+++ b/Source/devtools/front_end/flameChart.css
@@ -33,10 +33,19 @@
     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-entry-info {
+    position: absolute;
+    bottom: 20px;
+    left: 20px;
+    height: 120px;
+    background-color: rgba(255, 255, 255, 0.7);
+    pointer-events: none;
+}