Enable spare RenderProcessHost to be preinitialized.

chrome/browser/android/chrome_feature_list.cc

Index: chrome/browser/android/chrome_feature_list.cc
diff --git a/chrome/browser/android/chrome_feature_list.cc b/chrome/browser/android/chrome_feature_list.cc
index 7ef4fbad68d7d62d1daf4ea0be042469dc87f973..fac7dbe3747d004377fc03725ccd5f58f843fe9a 100644
--- a/chrome/browser/android/chrome_feature_list.cc
+++ b/chrome/browser/android/chrome_feature_list.cc
@@ -78,6 +78,7 @@ const base::Feature* kFeaturesExposedToJava[] = {
     &kNTPLaunchAfterInactivity,
     &kNTPOfflinePagesFeature,
     &NTPShowGoogleGInOmniboxFeature,
+    &kOmniboxSpareRenderer,
     &kPayWithGoogleV1,
     &kPhysicalWebFeature,
     &kPhysicalWebSharing,
@@ -217,6 +218,9 @@ const base::Feature kNTPOfflinePagesFeature{"NTPOfflinePages",
 const base::Feature NTPShowGoogleGInOmniboxFeature{
     "NTPShowGoogleGInOmnibox", base::FEATURE_DISABLED_BY_DEFAULT};
 
+const base::Feature kOmniboxSpareRenderer{"OmniboxSpareRenderer",
+                                          base::FEATURE_DISABLED_BY_DEFAULT};
+
 const base::Feature kPayWithGoogleV1{"PayWithGoogleV1",
                                      base::FEATURE_DISABLED_BY_DEFAULT};