DevTools: Refactor network panel overview

Source/devtools/front_end/network/networkPanel.css

Index: Source/devtools/front_end/network/networkPanel.css
diff --git a/Source/devtools/front_end/network/networkPanel.css b/Source/devtools/front_end/network/networkPanel.css
index fa6c21c234f8807291930743ed40fba99f92ce10..a81f5315d89eeb8f9cbb3a213d73cb23efaf7ac9 100644
--- a/Source/devtools/front_end/network/networkPanel.css
+++ b/Source/devtools/front_end/network/networkPanel.css
@@ -171,30 +171,22 @@
     width: 100%;
 }
 
+#network-overview-panel {
+    flex: none;
+    position: relative;
+}
+
 #network-overview-container {
     overflow: hidden;
     flex: auto;
     display: flex;
+    flex-direction: column;
     position: relative;
     border-bottom: 1px solid #CDCDCD;
 }
 
-.network-overview-canvas-container {
-    position: absolute;
-    top: 0;
-    right: 0;
-    bottom: 0;
-    left: 0;
-    z-index: 200;
-}
-
-.network-overview-canvas-container canvas {
-    width: 100%;
-    height: 100%;
-}
-
-#network-overview-grid {
-    flex: auto;
+#network-overview-grid .resources-dividers-label-bar {
+    pointer-events: auto;
 }
 
 .network .network-overview {