refactor: migrate base::ThreadPool() as trait to base::ThreadPool:: API (#22555)

shell/browser/api/electron_api_content_tracing.cc

@@ -8,6 +8,7 @@
 
 #include "base/files/file_util.h"
 #include "base/optional.h"
+#include "base/task/thread_pool.h"
 #include "base/threading/thread_restrictions.h"
 #include "content/public/browser/tracing_controller.h"
 #include "shell/common/gin_converters/callback_converter.h"
@@ -86,10 +87,8 @@ v8::Local<v8::Promise> StopRecording(gin_helper::Arguments* args) {
     StopTracing(std::move(promise), base::make_optional(path));
   } else {
     // use a temporary file.
-    base::PostTaskAndReplyWithResult(
-        FROM_HERE,
-        {base::ThreadPool(), base::MayBlock(),
-         base::TaskPriority::USER_VISIBLE},
+    base::ThreadPool::PostTaskAndReplyWithResult(
+        FROM_HERE, {base::MayBlock(), base::TaskPriority::USER_VISIBLE},
         base::BindOnce(CreateTemporaryFileOnIO),
         base::BindOnce(StopTracing, std::move(promise)));
   }

shell/browser/api/electron_api_net_log.cc

@@ -7,6 +7,7 @@
 #include <utility>
 
 #include "base/command_line.h"
+#include "base/task/thread_pool.h"
 #include "chrome/browser/browser_process.h"
 #include "components/net_log/chrome_net_log.h"
 #include "content/public/browser/storage_partition.h"
@@ -52,8 +53,8 @@ scoped_refptr<base::SequencedTaskRunner> CreateFileTaskRunner() {
   //
   // These operations can be skipped on shutdown since FileNetLogObserver's API
   // doesn't require things to have completed until notified of completion.
-  return base::CreateSequencedTaskRunner(
-      {base::ThreadPool(), base::MayBlock(), base::TaskPriority::USER_VISIBLE,
+  return base::ThreadPool::CreateSequencedTaskRunner(
+      {base::MayBlock(), base::TaskPriority::USER_VISIBLE,
        base::TaskShutdownBehavior::SKIP_ON_SHUTDOWN});
 }
 

shell/browser/api/electron_api_web_contents.cc

@@ -1949,9 +1949,8 @@ void WebContents::Print(gin_helper::Arguments* args) {
     settings.SetIntKey(printing::kSettingDpiVertical, dpi);
   }
 
-  base::PostTaskAndReplyWithResult(
-      FROM_HERE,
-      {base::ThreadPool(), base::MayBlock(), base::TaskPriority::USER_BLOCKING},
+  base::ThreadPool::PostTaskAndReplyWithResult(
+      FROM_HERE, {base::MayBlock(), base::TaskPriority::USER_BLOCKING},
       base::BindOnce(&GetDefaultPrinterAsync),
       base::BindOnce(&WebContents::OnGetDefaultPrinter,
                      weak_factory_.GetWeakPtr(), std::move(settings),