Bug 1648530, implement sidebar telemetry probes to track how often it was opened and what type of panel was viewed. r=jaws

Differential Revision: https://phabricator.services.mozilla.com/D81165

browser/base/content/browser-sidebar.js

@@ -444,6 +444,9 @@ var SidebarUI = {
    * @return {Promise<boolean>}
    */
   async show(commandID, triggerNode) {
+    let panelType = commandID.substring(4, commandID.length - 7);
+    Services.telemetry.keyedScalarAdd("sidebar.opened", panelType, 1);
+
     // Extensions without private window access wont be in the
     // sidebars map.
     if (!this.sidebars.has(commandID)) {
@@ -470,6 +473,9 @@ var SidebarUI = {
    * @return {Promise<boolean>}
    */
   async showInitially(commandID) {
+    let panelType = commandID.substring(4, commandID.length - 7);
+    Services.telemetry.keyedScalarAdd("sidebar.opened", panelType, 1);
+
     // Extensions without private window access wont be in the
     // sidebars map.
     if (!this.sidebars.has(commandID)) {

toolkit/components/telemetry/Scalars.yaml

@@ -1709,6 +1709,23 @@ findbar:
       - 'main'
 
 sidebar:
+  opened:
+    bug_numbers:
+      - 1648530
+    description: >
+      The number of times the sidebar was opened, per view (e.g.: bookmarks, history,
+      synced tabs).
+    expires: never
+    kind: uint
+    keyed: true
+    notification_emails:
+      - emalysz@mozilla.com
+      - rtestard@mozilla.com
+    release_channel_collection: opt-out
+    products:
+      - 'firefox'
+    record_in_processes:
+      - 'main'
   search:
     bug_numbers:
       - 1648524