Add UMA for showing sidebar panes

Backend CL: https://crrev.com/c/2378025

Bug: chromium:1119895
Change-Id: I5c24b4b49437cea977bcdddc6327cb3702fa88c4
Reviewed-on: https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/2377585
Reviewed-by: Mathias Bynens <[email protected]>
Reviewed-by: Patrick Brosset <[email protected]>
Reviewed-by: Alex Rudenko <[email protected]>
Commit-Queue: Changhao Han <[email protected]>
diff --git a/front_end/devtools_compatibility.js b/front_end/devtools_compatibility.js
index e927f03..6626e40 100644
--- a/front_end/devtools_compatibility.js
+++ b/front_end/devtools_compatibility.js
@@ -366,6 +366,7 @@
     ColorPickerFixedColor: 'DevTools.ColorPicker.FixedColor',
     PanelClosed: 'DevTools.PanelClosed',
     PanelShown: 'DevTools.PanelShown',
+    SidebarPaneShown: 'DevTools.SidebarPaneShown',
     KeyboardShortcutFired: 'DevTools.KeyboardShortcutFired',
     IssuesPanelOpenedFrom: 'DevTools.IssuesPanelOpenedFrom',
     KeybindSetSettingChanged: 'DevTools.KeybindSetSettingChanged',