Bug 1585330 - Add more log in browsertime_pageload.js r=rwood

Adds log info in browsertime_pageload.js

Differential Revision: https://phabricator.services.mozilla.com/D47784

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

testing/raptor/browsertime/browsertime_pageload.js

@@ -1,16 +1,24 @@
 /* eslint-env node */
 
 module.exports = async function(context, commands) {
+  context.log.info("Starting a browsertime pageload");
   let url = context.options.browsertime.url;
   let page_cycles = context.options.browsertime.page_cycles;
   let page_cycle_delay = context.options.browsertime.page_cycle_delay;
+  let foreground_delay = context.options.browsertime.foreground_delay;
 
-  await commands.wait.byTime(context.options.browsertime.foreground_delay);
+  context.log.info("Waiting for %d ms (foreground_delay)", foreground_delay);
+  await commands.wait.byTime(foreground_delay);
+
+  context.log.info("Navigating to about:blank");
   await commands.navigate("about:blank");
 
   for (let count = 0; count < page_cycles; count++) {
+    context.log.info("Cycle %d, waiting for %d ms", count, page_cycle_delay);
     await commands.wait.byTime(page_cycle_delay);
+    context.log.info("Cycle %d, starting the measure", count);
     await commands.measure.start(url);
   }
+  context.log.info("Browsertime pageload ended.");
   return true;
 };