Worker: Remove a runtime flag for nested dedicated workers

Nested dedicated workers has been enabled by default since Chrome 69:
https://www.chromestatus.com/feature/6080438103703552

Bug: 31666
Change-Id: I12785dd8c1d5582ae0d069b5b6993ad50c6be9b3
Reviewed-on: https://chromium-review.googlesource.com/c/1325596Reviewed-by: Nate Chapin <japhet@chromium.org>
Reviewed-by: Kinuko Yasuda <kinuko@chromium.org>
Commit-Queue: Hiroki Nakagawa <nhiroki@chromium.org>
Cr-Commit-Position: refs/heads/master@{#608244}

content/child/runtime_features.cc

@@ -437,9 +437,6 @@ void SetRuntimeFeaturesDefaultsAndUpdateFromArgs(
     WebRuntimeFeatures::EnablePreloadImageSrcSetEnabled(true);
   }
 
-  WebRuntimeFeatures::EnableNestedWorkers(
-      base::FeatureList::IsEnabled(blink::features::kNestedWorkers));
-
   if (base::FeatureList::IsEnabled(
           features::kExperimentalProductivityFeatures)) {
     WebRuntimeFeatures::EnableExperimentalProductivityFeatures(true);

third_party/blink/common/features.cc

@@ -32,10 +32,6 @@ const base::Feature kLayoutNG{"LayoutNG", base::FEATURE_DISABLED_BY_DEFAULT};
 const base::Feature kMojoBlobURLs{"MojoBlobURLs",
                                   base::FEATURE_DISABLED_BY_DEFAULT};
 
-// Nested workers. See https://crbug.com/31666
-const base::Feature kNestedWorkers{"NestedWorkers",
-                                   base::FEATURE_ENABLED_BY_DEFAULT};
-
 // Onion souping for all DOMStorage. https://crbug.com/781870
 const base::Feature kOnionSoupDOMStorage{"OnionSoupDOMStorage",
                                          base::FEATURE_ENABLED_BY_DEFAULT};

third_party/blink/public/common/features.h

@@ -18,7 +18,6 @@ BLINK_COMMON_EXPORT extern const base::Feature
     kEnableGpuRasterizationViewportRestriction;
 BLINK_COMMON_EXPORT extern const base::Feature kLayoutNG;
 BLINK_COMMON_EXPORT extern const base::Feature kMojoBlobURLs;
-BLINK_COMMON_EXPORT extern const base::Feature kNestedWorkers;
 BLINK_COMMON_EXPORT extern const base::Feature kOnionSoupDOMStorage;
 BLINK_COMMON_EXPORT extern const base::Feature kPortals;
 BLINK_COMMON_EXPORT extern const base::Feature kRecordAnchorMetricsClicked;

third_party/blink/public/platform/web_runtime_features.h

@@ -119,7 +119,6 @@ class WebRuntimeFeatures {
   BLINK_PLATFORM_EXPORT static void EnableMiddleClickAutoscroll(bool);
   BLINK_PLATFORM_EXPORT static void EnableModernMediaControls(bool);
   BLINK_PLATFORM_EXPORT static void EnableNavigatorContentUtils(bool);
-  BLINK_PLATFORM_EXPORT static void EnableNestedWorkers(bool);
   BLINK_PLATFORM_EXPORT static void EnableNetInfoDownlinkMax(bool);
   BLINK_PLATFORM_EXPORT static void EnableNetworkService(bool);
   BLINK_PLATFORM_EXPORT static void EnableNoHoverAfterLayoutChange(bool);

third_party/blink/renderer/core/workers/worker.idl

@@ -31,7 +31,7 @@
     ActiveScriptWrappable,
     Constructor(DOMString scriptURL, optional WorkerOptions options),
     ConstructorCallWith=ExecutionContext,
-    Exposed(Window StableBlinkFeatures,DedicatedWorker NestedWorkers),
+    Exposed=(Window,DedicatedWorker),
     RaisesException=Constructor,
     ImplementedAs=DedicatedWorker
 ] interface Worker : EventTarget {

third_party/blink/renderer/platform/exported/web_runtime_features.cc

@@ -252,10 +252,6 @@ void WebRuntimeFeatures::EnableNavigatorContentUtils(bool enable) {
   RuntimeEnabledFeatures::SetNavigatorContentUtilsEnabled(enable);
 }
 
-void WebRuntimeFeatures::EnableNestedWorkers(bool enable) {
-  RuntimeEnabledFeatures::SetNestedWorkersEnabled(enable);
-}
-
 void WebRuntimeFeatures::EnableNetInfoDownlinkMax(bool enable) {
   RuntimeEnabledFeatures::SetNetInfoDownlinkMaxEnabled(enable);
 }

third_party/blink/renderer/platform/runtime_enabled_features.json5

@@ -797,10 +797,6 @@
       name: "NavigatorDeviceMemory",
       status: "stable",
     },
-    {
-      name: "NestedWorkers",
-      status: "stable",
-    },
     {
       name: "NetInfoDownlinkMax",
       status: "stable",