Remove unused "DisableJavascriptOptimizerByDefault" variations flag

BUG=393153126

Change-Id: Iaf259f0d5e9b7c23308b6963d89f9a5f6587925e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6216899
Commit-Queue: Peter Kotwicz <pkotwicz@chromium.org>
Reviewed-by: Javier Castro <jacastro@chromium.org>
Reviewed-by: Yaron Friedman <yfriedman@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1413633}
diff --git a/chrome/browser/chrome_content_browser_client.cc b/chrome/browser/chrome_content_browser_client.cc
index 8f6563d4..9c3baf9a 100644
--- a/chrome/browser/chrome_content_browser_client.cc
+++ b/chrome/browser/chrome_content_browser_client.cc
@@ -843,10 +843,6 @@
              "SkipPagehideInCommitForDSENavigation",
              base::FEATURE_DISABLED_BY_DEFAULT);
 
-BASE_FEATURE(kDisableJavascriptOptimizerByDefault,
-             "DisableJavascriptOptimizerByDefault",
-             base::FEATURE_DISABLED_BY_DEFAULT);
-
 // A small ChromeBrowserMainExtraParts that invokes a callback when threads are
 // ready. Used to initialize ChromeContentBrowserClient data that needs the UI
 // thread.
@@ -7881,14 +7877,6 @@
            CONTENT_SETTING_BLOCK;
   }
 
-  // Activate experiment only for users who haven't explicitly disabled v8
-  // optimization by default so that most of the users in the "experiment
-  // off" branch have v8 optimization enabled.
-  if (base::FeatureList::GetInstance()->IsEnabled(
-          kDisableJavascriptOptimizerByDefault)) {
-    return true;
-  }
-
   return (map &&
           map->GetContentSetting(site_url, site_url,
                                  ContentSettingsType::JAVASCRIPT_OPTIMIZER) ==
diff --git a/chrome/browser/renderer_host/javascript_optimizer_feature_browsertest.cc b/chrome/browser/renderer_host/javascript_optimizer_feature_browsertest.cc
index 87099533..20511a8 100644
--- a/chrome/browser/renderer_host/javascript_optimizer_feature_browsertest.cc
+++ b/chrome/browser/renderer_host/javascript_optimizer_feature_browsertest.cc
@@ -2,7 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "base/test/scoped_feature_list.h"
 #include "chrome/browser/content_settings/host_content_settings_map_factory.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/ui/browser.h"
@@ -20,10 +19,6 @@
 
 namespace {
 
-BASE_FEATURE(kDisableJavascriptOptimizerByDefault,
-             "DisableJavascriptOptimizerByDefault",
-             base::FEATURE_DISABLED_BY_DEFAULT);
-
 bool AreV8OptimizationsDisabledOnActiveWebContents(Browser* browser) {
   content::WebContents* web_contents =
       browser->GetActiveTabInterface()->GetContents();
@@ -34,45 +29,10 @@
 
 }  // namespace
 
-class JavascriptOptimizerFeatureBrowserTest
-    : public InProcessBrowserTest,
-      public testing::WithParamInterface<bool> {
- public:
-  JavascriptOptimizerFeatureBrowserTest() {
-    if (GetParam()) {
-      scoped_feature_list_.InitAndEnableFeature(
-          kDisableJavascriptOptimizerByDefault);
-    } else {
-      scoped_feature_list_.InitAndDisableFeature(
-          kDisableJavascriptOptimizerByDefault);
-    }
-  }
-
- private:
-  base::test::ScopedFeatureList scoped_feature_list_;
-};
-
-// Tests the effect of the DisableJavascriptOptimizerByDefault feature
-// flag.
-IN_PROC_BROWSER_TEST_P(JavascriptOptimizerFeatureBrowserTest,
-                       CheckFeatureHasEffect) {
-  ASSERT_TRUE(embedded_test_server()->Start());
-  ASSERT_TRUE(ui_test_utils::NavigateToURL(
-      browser(), embedded_test_server()->GetURL("/simple.html")));
-
-  EXPECT_EQ(GetParam(),
-            AreV8OptimizationsDisabledOnActiveWebContents(browser()));
-}
-
-INSTANTIATE_TEST_SUITE_P(All,
-                         JavascriptOptimizerFeatureBrowserTest,
-                         testing::Values(true, false));
-
 typedef InProcessBrowserTest JavascriptOptimizerBrowserTest;
 
 // Test that V8 optimization is disabled when the user disables v8 optimization
-// by default via chrome://settings regardless of the status of the
-// DisableJavascriptOptimizerByDefault experiment.
+// by default via chrome://settings.
 IN_PROC_BROWSER_TEST_F(JavascriptOptimizerBrowserTest,
                        V8SiteSettingDefaultOff) {
   ASSERT_TRUE(embedded_test_server()->Start());
@@ -88,8 +48,7 @@
 }
 
 // Test that V8 optimization is disabled when the user disables v8 optimization
-// via chrome://settings for a specific site regardless of the status of the
-// DisableJavascriptOptimizerByDefault experiment.
+// via chrome://settings for a specific site.
 IN_PROC_BROWSER_TEST_F(JavascriptOptimizerBrowserTest,
                        DisabledViaSiteSpecificSetting) {
   ASSERT_TRUE(embedded_test_server()->Start());