Enable automatic page load instrumentation (#2084)

* Enable automatic page load instrumentation

* Remove glean.js legacy debugging methods

Glean.js now allows turning debugging on
directly from the browser console, deprecating
the need to set env variables at server startup
time. We retain the 'source tags' option in case
this is currently used to tag automation tests.

* Record page loads using standard events

rollup.config.js

@@ -111,12 +111,6 @@ export default {
       "process.env.NODE_ENV": JSON.stringify(
         production ? "production" : "development"
       ),
-      // These environment variables are always strings,
-      // so _any_ value will be read as `true` here
-      // i.e. GLEAN_LOG_PINGS=false will become `true` here.
-      // The only option when GLEAN_LOG_PINGS is `false` is when it is not set at all
-      GLEAN_LOG_PINGS: !!process.env.GLEAN_LOG_PINGS,
-      GLEAN_DEBUG_VIEW_TAG: process.env.GLEAN_DEBUG_VIEW_TAG || "",
       GLEAN_SOURCE_TAGS: process.env.GLEAN_SOURCE_TAGS || "",
       __DISPLAY_VERSION__: execSync("git describe --abbrev=0 --tags")
         .toString()

src/telemetry/index.js

@@ -1,8 +1,10 @@
 // ESlint does not support subpath exports, which are used by Glean.
 // https://github.com/import-js/eslint-plugin-import/issues/1868
 //
-// eslint-disable-next-line import/no-unresolved
+/* eslint-disable import/no-unresolved */
 import Glean from "@mozilla/glean/web";
+import GleanMetrics from "@mozilla/glean/metrics";
+/* eslint-enable import/no-unresolved */
 
 import { googleAnalytics } from "./ga";
 
@@ -42,17 +44,6 @@ export function initializeTelemetry() {
   });
 
   /* eslint-disable no-undef, no-constant-condition */
-
-  // GLEAN_LOG_PINGS is a boolean value,
-  // thus it should not have quotes around it.
-  if (GLEAN_LOG_PINGS === true) {
-    Glean.setLogPings(true);
-  }
-
-  if ("GLEAN_DEBUG_VIEW_TAG") {
-    Glean.setDebugViewTag("GLEAN_DEBUG_VIEW_TAG");
-  }
-
   if ("GLEAN_SOURCE_TAGS") {
     // GLEAN_SOURCE_TAGS is supposed to be a comma separated string of tags
     const sourceTags = "GLEAN_SOURCE_TAGS".split(",").map((tag) => tag.trim());
@@ -74,6 +65,9 @@ export function submitPageViewTelemetry(path) {
     ga("send", "pageview");
   }
 
+  // Use the standard events.
+  GleanMetrics.pageLoad({ url: path });
+
   // Send telemetry to Glean.
   pageMetrics.loaded.set();
   // Remove query params and trailing `/` characters.