Bug 1868480 - Record usage of the message composition window in Telemetry. r=aleca

Depends on D195611

Differential Revision: https://phabricator.services.mozilla.com/D195612

--HG--
extra : moz-landing-system : lando

mail/components/telemetry/Scalars.yaml

@@ -557,6 +557,22 @@ tb.ui.interaction:
     record_in_processes:
       - "main"
 
+  message_compose:
+    bug_numbers:
+      - 1868480
+    description: >
+      Records a count of interactions with items in the message composer.
+    expires: never
+    kind: uint
+    keyed: true
+    notification_emails:
+      - "telemetry-client-dev@thunderbird.net"
+    products:
+      - "thunderbird"
+    release_channel_collection: opt-out
+    record_in_processes:
+      - "main"
+
   message_display:
     bug_numbers:
       - 1736739

mail/modules/MailUsageTelemetry.jsm

@@ -11,12 +11,13 @@ const EXPORTED_SYMBOLS = ["MailUsageTelemetry"];
 const DOMWINDOW_OPENED_TOPIC = "domwindowopened";
 
 // Window types we're interested in.
-const WINDOW_TYPES = ["mail:3pane", "mail:messageWindow"];
+const WINDOW_TYPES = ["mail:3pane", "mail:messageWindow", "msgcompose"];
 
 // Window URLs we're interested in.
 const WINDOW_URLS = [
   "chrome://messenger/content/messenger.xhtml",
   "chrome://messenger/content/messageWindow.xhtml",
+  "chrome://messenger/content/messengercompose/messengercompose.xhtml",
   "about:3pane",
   "about:addressbook",
   "about:message",
@@ -65,6 +66,9 @@ const MESSENGER_UI_CONTAINER_IDS = {
   chatContextMenu: "chat",
   participantListContextMenu: "chat",
 
+  // Message composition.
+  msgcomposeWindow: "message-compose",
+
   // Anything to do with the 3-pane tab or message window.
   folderPaneHeaderBar: "message-display",
   folderPaneGetMessagesContext: "message-display",
@@ -318,7 +322,10 @@ let MailUsageTelemetry = {
     }
 
     // This is what events targeted at content will actually look like.
-    if (sourceEvent.target.localName == "browser") {
+    if (
+      sourceEvent.target.localName == "browser" ||
+      sourceEvent.target.localName == "editor"
+    ) {
       return;
     }