[DevTools] Add power profiler and power overview in timeline panel.

Source/devtools/front_end/timelinePanel.css

Index: Source/devtools/front_end/timelinePanel.css
diff --git a/Source/devtools/front_end/timelinePanel.css b/Source/devtools/front_end/timelinePanel.css
index 62b157363a68a04483836f724396b9003eba6b98..ba869a0d83975d8b8a5239a4721986956485b0e0 100644
--- a/Source/devtools/front_end/timelinePanel.css
+++ b/Source/devtools/front_end/timelinePanel.css
@@ -265,7 +265,8 @@
 }
 
 #timeline-overview-events,
-#timeline-overview-memory {
+#timeline-overview-memory,
+#timeline-overview-power {
     position: absolute;
     left: 0;
     right: 0;
@@ -274,7 +275,8 @@
     z-index: 160;
 }
 
-#timeline-overview-memory  {
+#timeline-overview-memory,
+#timeline-overview-power  {
     top: 25px;
 }
 
@@ -474,6 +476,10 @@
     -webkit-mask-position: -224px -48px;
 }
 
+.timeline-overview-sidebar-power .icon {
+    -webkit-mask-position: -64px -120px;
+}
+
 .memory-graph-label {
     position: absolute;
     left: 5px;