[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 91e432b308d2e0f38023f7755b28417f63032c6a..1634ee531c6c808d3261b1d798bf6e775447e834 100644
--- a/Source/devtools/front_end/timelinePanel.css
+++ b/Source/devtools/front_end/timelinePanel.css
@@ -33,6 +33,12 @@
     border-bottom: 1px solid rgb(140, 140, 140);
 }
 
+#timeline-overview-panel.power-overview {
+    flex: 0 0 106px;
+    position: relative;
+    border-bottom: 1px solid rgb(140, 140, 140);
+}
+
 #timeline-overview-panel .timeline-graph-bar {
     pointer-events: none;
 }
@@ -86,6 +92,15 @@
     height: 80px;
 }
 
+
+#timeline-overview-grid.power-overview #resources-graphs {
+    position: absolute;
+    top: 0;
+    left: 0;
+    right: 0;
+    height: 105px;
+}
+
 #timeline-container {
     border-right: 0 none transparent;
     overflow-y: scroll;
@@ -265,7 +280,8 @@
 }
 
 #timeline-overview-events,
-#timeline-overview-memory {
+#timeline-overview-memory,
+#timeline-overview-power {
     position: absolute;
     left: 0;
     right: 0;
@@ -274,7 +290,8 @@
     z-index: 160;
 }
 
-#timeline-overview-memory  {
+#timeline-overview-memory,
+#timeline-overview-power  {
     top: 25px;
 }
 
@@ -474,6 +491,10 @@
     -webkit-mask-position: -224px -48px;
 }
 
+.timeline-overview-sidebar-power .icon {
+    -webkit-mask-position: -64px -120px;
+}
+
 .memory-graph-label {
     position: absolute;
     left: 5px;