Add feature config for finching concurrent inlining

Bug: chromium:1031988
Change-Id: I6cba869a4365b24fff4b44d6add03608ce004e4a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1954515
Reviewed-by: Brian White <bcwhite@chromium.org>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Commit-Queue: Maya Lekova <mslekova@chromium.org>
Cr-Commit-Position: refs/heads/master@{#723811}

gin/gin_features.cc

@@ -38,4 +38,8 @@ const base::Feature kV8GCLessCompaction{"V8GCLessCompaction",
 const base::Feature kV8GCAlwaysPromoteYoungMC{
     "V8GCAlwaysPromoteYoungMC", base::FEATURE_DISABLED_BY_DEFAULT};
 
+// Enable concurrent inlining in TurboFan.
+const base::Feature kV8ConcurrentInlining{"V8ConcurrentInlining",
+                                          base::FEATURE_DISABLED_BY_DEFAULT};
+
 }  // namespace features

gin/gin_features.h

@@ -18,6 +18,7 @@ GIN_EXPORT extern const base::Feature kV8HugeMaxOldGenerationSize;
 GIN_EXPORT extern const base::Feature kV8GCBackgroundSchedule;
 GIN_EXPORT extern const base::Feature kV8GCLessCompaction;
 GIN_EXPORT extern const base::Feature kV8GCAlwaysPromoteYoungMC;
+GIN_EXPORT extern const base::Feature kV8ConcurrentInlining;
 
 }  // namespace features
 

gin/v8_initializer.cc

@@ -254,6 +254,13 @@ void V8Initializer::Initialize(IsolateHolder::ScriptMode mode) {
         sizeof(gc_experiment_always_promote_young_mc) - 1);
   }
 
+  if (base::FeatureList::IsEnabled(features::kV8ConcurrentInlining)) {
+    static const char tf_experiment_concurrent_inlining[] =
+        "--concurrent_inlining";
+    v8::V8::SetFlagsFromString(tf_experiment_concurrent_inlining,
+                               sizeof(tf_experiment_concurrent_inlining) - 1);
+  }
+
   if (IsolateHolder::kStrictMode == mode) {
     static const char use_strict[] = "--use_strict";
     v8::V8::SetFlagsFromString(use_strict, sizeof(use_strict) - 1);

testing/variations/fieldtrial_testing_config.json

@@ -7024,6 +7024,31 @@
             ]
         }
     ],
+    "V8ConcurrentInlining": [
+        {
+            "platforms": [
+                "android",
+                "chromeos",
+                "linux",
+                "mac",
+                "windows"
+            ],
+            "experiments": [
+                {
+                    "name": "Disabled",
+                    "disable_features": [
+                        "V8ConcurrentInlining"
+                    ]
+                },
+                {
+                    "name": "Enabled",
+                    "enable_features": [
+                        "V8ConcurrentInlining"
+                    ]
+                }
+            ]
+        }
+    ],
     "V8LowMemoryModeForSubframes": [
         {
             "platforms": [