Add a NoStatePrefetch entry in about://flags

chrome/browser/about_flags.cc

Index: chrome/browser/about_flags.cc
diff --git a/chrome/browser/about_flags.cc b/chrome/browser/about_flags.cc
index 2950c5e0ad7a23851d62ff96ec90ad80cadeeea0..9d71b7de345efb635fe9d07beb96f482a23a060b 100644
--- a/chrome/browser/about_flags.cc
+++ b/chrome/browser/about_flags.cc
@@ -26,6 +26,7 @@
 #include "base/values.h"
 #include "build/build_config.h"
 #include "cc/base/switches.h"
+#include "chrome/browser/prerender/prerender_field_trial.h"
 #include "chrome/common/channel_info.h"
 #include "chrome/common/chrome_content_client.h"
 #include "chrome/common/chrome_features.h"
@@ -641,6 +642,26 @@ const FeatureEntry::Choice kEnableDefaultMediaSessionChoices[] = {
 };
 #endif  // !defined(OS_ANDROID)
 
+const FeatureEntry::FeatureParam kNoStatePrefetchEnabled[] = {
+    {prerender::kNoStatePrefetchFeatureModeParameterName,
+     prerender::kNoStatePrefetchFeatureModeParameterPrefetch}};
+
+const FeatureEntry::FeatureParam kNoStatePrefetchPrerender[] = {
+    {prerender::kNoStatePrefetchFeatureModeParameterName,
+     prerender::kNoStatePrefetchFeatureModeParameterPrerender}};
+
+const FeatureEntry::FeatureParam kNoStatePrefetchSimpleLoad[] = {
+    {prerender::kNoStatePrefetchFeatureModeParameterName,
+     prerender::kNoStatePrefetchFeatureModeParameterSimpleLoad}};
+
+const FeatureEntry::FeatureVariation kNoStatePrefetchFeatureVariations[] = {
+    {"No-state prefetch", kNoStatePrefetchEnabled,
+     arraysize(kNoStatePrefetchEnabled), nullptr},
+    {"Prerender", kNoStatePrefetchPrerender,
+     arraysize(kNoStatePrefetchPrerender), nullptr},
+    {"Simple load", kNoStatePrefetchSimpleLoad,
+     arraysize(kNoStatePrefetchSimpleLoad), nullptr}};
+
 // RECORDING USER METRICS FOR FLAGS:
 // -----------------------------------------------------------------------------
 // The first line of the entry is the internal name.
@@ -2117,6 +2138,11 @@ const FeatureEntry kFeatureEntries[] = {
      IDS_FLAGS_COMPONENT_FLASH_ONLY_DESCRIPTION, kOsCrOS,
      FEATURE_VALUE_TYPE(features::kComponentFlashOnly)},
 #endif
+    {"enable-nostate-prefetch", IDS_FLAGS_NOSTATE_PREFETCH,
+     IDS_FLAGS_NOSTATE_PREFETCH_DESCRIPTION, kOsAll,
+     FEATURE_WITH_VARIATIONS_VALUE_TYPE(prerender::kNoStatePrefetchFeature,
+                                        kNoStatePrefetchFeatureVariations,
+                                        "NoStatePrefetchValidation")},
 
     // NOTE: Adding new command-line switches requires adding corresponding
     // entries to enum "LoginCustomFlags" in histograms.xml. See note in