DevTools: [timeline] Include other thread costs in overview

Source/devtools/front_end/timeline/timelinePanel.css

Index: Source/devtools/front_end/timeline/timelinePanel.css
diff --git a/Source/devtools/front_end/timeline/timelinePanel.css b/Source/devtools/front_end/timeline/timelinePanel.css
index a85fb1ce32d2b73fe6686445a9eb5f36ad31c07d..af08db600d24e496cb6fcfd494d5889e087245ae 100644
--- a/Source/devtools/front_end/timeline/timelinePanel.css
+++ b/Source/devtools/front_end/timeline/timelinePanel.css
@@ -268,7 +268,7 @@
     flex-basis: 25px;
 }
 
-#timeline-overview-main-thread,
+#timeline-overview-cpu-activity,
 #timeline-overview-framerate,
 #timeline-overview-memory {
     flex-basis: 21px;
@@ -297,10 +297,15 @@
     display: none;
 }
 
-#timeline-overview-main-thread::before {
+#timeline-overview-cpu-activity::before {
     content: "100%";
 }
 
+#timeline-overview-cpu-activity .background {
+    opacity: 0.15;
+    z-index: -10;
+}
+
 #timeline-overview-framerate::before {
     content: "60 fps";
 }