service worker: Remove kOffMainThreadServiceWorkerStartup flag

This feature was fully launched in M80.

Bug: 692909
Change-Id: Ie66c1ac291092cca58c4cab9f291b79b0eae343e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2071521Reviewed-by: Matt Falkenhagen <falken@chromium.org>
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Reviewed-by: Kinuko Yasuda <kinuko@chromium.org>
Reviewed-by: Hiroki Nakagawa <nhiroki@chromium.org>
Commit-Queue: Kinuko Yasuda <kinuko@chromium.org>
Cr-Commit-Position: refs/heads/master@{#747232}

content/renderer/browser_exposed_renderer_interfaces.cc

@@ -29,7 +29,6 @@
 #include "mojo/public/cpp/bindings/binder_map.h"
 #include "mojo/public/cpp/bindings/pending_receiver.h"
 #include "mojo/public/cpp/bindings/self_owned_receiver.h"
-#include "third_party/blink/public/common/features.h"
 #include "v8/include/v8.h"
 
 namespace content {
@@ -194,23 +193,14 @@ void ExposeRendererInterfacesToBrowser(
   binders->Add(base::BindRepeating(&CreateResourceUsageReporter, render_thread),
                base::ThreadTaskRunnerHandle::Get());
 
-  if (base::FeatureList::IsEnabled(
-          blink::features::kOffMainThreadServiceWorkerStartup)) {
-    auto task_runner = base::ThreadPool::CreateSingleThreadTaskRunner(
-        {base::MayBlock(), base::TaskPriority::USER_BLOCKING,
-         base::TaskShutdownBehavior::SKIP_ON_SHUTDOWN});
-    binders->Add(
-        base::BindRepeating(&EmbeddedWorkerInstanceClientImpl::CreateForRequest,
-                            task_runner),
-        task_runner);
-  } else {
-    auto task_runner =
-        render_thread->GetWebMainThreadScheduler()->DefaultTaskRunner();
-    binders->Add(
-        base::BindRepeating(&EmbeddedWorkerInstanceClientImpl::CreateForRequest,
-                            task_runner),
-        task_runner);
-  }
+  auto task_runner_for_service_worker_startup =
+      base::ThreadPool::CreateSingleThreadTaskRunner(
+          {base::MayBlock(), base::TaskPriority::USER_BLOCKING,
+           base::TaskShutdownBehavior::SKIP_ON_SHUTDOWN});
+  binders->Add(
+      base::BindRepeating(&EmbeddedWorkerInstanceClientImpl::CreateForRequest,
+                          task_runner_for_service_worker_startup),
+      task_runner_for_service_worker_startup);
 
   binders->Add(base::BindRepeating(&CreateFrameFactory),
                base::ThreadTaskRunnerHandle::Get());

third_party/blink/common/features.cc

@@ -82,11 +82,6 @@ const base::Feature kNavigationPredictor {
 #endif
 };
 
-// Start service workers on a background thread.
-// https://crbug.com/692909
-const base::Feature kOffMainThreadServiceWorkerStartup{
-    "OffMainThreadServiceWorkerStartup", base::FEATURE_ENABLED_BY_DEFAULT};
-
 // Enable browser-initiated dedicated worker script loading
 // (PlzDedicatedWorker). https://crbug.com/906991
 const base::Feature kPlzDedicatedWorker{"PlzDedicatedWorker",

third_party/blink/public/common/features.h

@@ -34,8 +34,6 @@ BLINK_COMMON_EXPORT extern const base::Feature kJSONModules;
 BLINK_COMMON_EXPORT extern const base::Feature kLayoutNG;
 BLINK_COMMON_EXPORT extern const base::Feature kMixedContentAutoupgrade;
 BLINK_COMMON_EXPORT extern const base::Feature kNavigationPredictor;
-BLINK_COMMON_EXPORT extern const base::Feature
-    kOffMainThreadServiceWorkerStartup;
 BLINK_COMMON_EXPORT extern const base::Feature kPlzDedicatedWorker;
 BLINK_COMMON_EXPORT extern const base::Feature kPortals;
 BLINK_COMMON_EXPORT extern const base::Feature kPortalsCrossOrigin;