Stop initializing SharedWorkerWatcher instances

There's an issue with how SharedWorkerWatcher handles shared workers
with a file: URL. This CL avoids reverting the bigger CL that introduce
the SharedWorkerWatcher class while still avoiding the issue.

Bug: 1013168
Change-Id: I4524c4c8b1ae85b56ec22bc49e0f7ddb0bd5a27b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1852944
Commit-Queue: Patrick Monette <pmonette@chromium.org>
Reviewed-by: Sigurður Ásgeirsson <siggi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#704647}

chrome/browser/performance_manager/chrome_browser_main_extra_parts_performance_manager.cc

@@ -127,13 +127,11 @@ void ChromeBrowserMainExtraPartsPerformanceManager::Observe(
     const content::NotificationDetails& details) {
   switch (type) {
     case chrome::NOTIFICATION_PROFILE_CREATED: {
-      Profile* profile = content::Source<Profile>(source).ptr();
-      CreateSharedWorkerWatcher(profile);
+      // TODO(1013168): Create the worker watchers here.
       break;
     }
     case chrome::NOTIFICATION_PROFILE_DESTROYED: {
-      Profile* profile = content::Source<Profile>(source).ptr();
-      DeleteSharedWorkerWatcher(profile);
+      // TODO(1013168): Delete the worker watchers here.
       break;
     }
     default: