Migrate off BrowserThread::DeleteSoon in /content/shell

Instead use base::DeleteSoon which enforces usage of TaskTraits.

This CL is a no-op as-is. It was recently discovered however that some
callers did BrowserThread::DeleteSoon() with pending tasks running on
different task queues (different traits  -- e.g.

TaskTraits to make this more obvious. Please review whether calls in
this CL can be migrated as-is or need additional traits to match
potentially pending tasks.

Split from https://chromium-review.googlesource.com/c/chromium/src/+/1894109
for cursory review.

This CL was uploaded by git cl split.

R=peter@chromium.org


TaskPriority: :BEST_EFFORT) which can result in out-of-order deletion...
BrowserThread: :DeleteSoon() is being migrated to base::DeleteSoon() w/
Bug: 1019767
Change-Id: Iab1b207a72afe4f2cc0b57d3fb97223282fe071c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1893540
Auto-Submit: Gabriel Charette <gab@chromium.org>
Reviewed-by: Peter Beverloo <peter@chromium.org>
Commit-Queue: Peter Beverloo <peter@chromium.org>
Cr-Commit-Position: refs/heads/master@{#713408}

content/shell/browser/shell_browser_context.cc

@@ -78,8 +78,8 @@ ShellBrowserContext::~ShellBrowserContext() {
   // outstanding request while URLRequestContext's destructor ensures that there
   // are no more outstanding requests.
   if (resource_context_) {
-    BrowserThread::DeleteSoon(
-      BrowserThread::IO, FROM_HERE, resource_context_.release());
+    base::DeleteSoon(FROM_HERE, {BrowserThread::IO},
+                     resource_context_.release());
   }
   ShutdownStoragePartitions();
 }