Expose --site-per-process in chrome://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 decc6fe7e57135014e73ba483cd2ab607ccc6f92..991de74a944b4d8de462d7903792e9bd7ec2d522 100644
--- a/chrome/browser/about_flags.cc
+++ b/chrome/browser/about_flags.cc
@@ -2151,6 +2151,14 @@ const Experiment kExperiments[] = {
      MULTI_VALUE_TYPE(kMarkNonSecureAsChoices)
   },
 
+  {
+    "enable-site-per-process",
+    IDS_FLAGS_ENABLE_SITE_PER_PROCESS_NAME,
+    IDS_FLAGS_ENABLE_SITE_PER_PROCESS_DESCRIPTION,
+    kOsAll,
+    SINGLE_VALUE_TYPE(switches::kSitePerProcess)
+  },
+
   // NOTE: Adding new command-line switches requires adding corresponding
   // entries to enum "LoginCustomFlags" in histograms.xml. See note in
   // histograms.xml and don't forget to run AboutFlagsHistogramTest unit test.