DevTools: Fix network overview on hidpi

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 82151e9f668048c63710e9a757f5921d84f020a7..bf91d22b123232c902ba29a4611d7498fb393178 100644
--- a/Source/devtools/front_end/network/networkPanel.css
+++ b/Source/devtools/front_end/network/networkPanel.css
@@ -185,6 +185,11 @@
     border-bottom: 1px solid #CDCDCD;
 }
 
+#network-overview-container canvas {
+    width: 100%;
+    height: 100%;
+}
+
 #network-overview-grid .resources-dividers-label-bar {
     pointer-events: auto;
 }