Add a feature to enable User Data snapshots during development

Bug: 958893
Change-Id: I65e220fd47755686ef3a2a58468de2a640473c8a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2013361
Commit-Queue: Yann Dago <[email protected]>
Reviewed-by: Scott Violet <[email protected]>
Cr-Commit-Position: refs/heads/master@{#734977}
diff --git a/chrome/browser/about_flags.cc b/chrome/browser/about_flags.cc
index ab3e695..1e27b29 100644
--- a/chrome/browser/about_flags.cc
+++ b/chrome/browser/about_flags.cc
@@ -4867,6 +4867,13 @@
      flag_descriptions::kFreezeUserAgentDescription, kOsDesktop | kOsAndroid,
      FEATURE_VALUE_TYPE(blink::features::kFreezeUserAgent)},
 
+#if !defined(OS_ANDROID) && !defined(OS_CHROMEOS)
+    {"enable-user-data-snapshot", flag_descriptions::kUserDataSnapshotName,
+     flag_descriptions::kUserDataSnapshotDescription,
+     kOsMac | kOsWin | kOsLinux,
+     FEATURE_VALUE_TYPE(features::kUserDataSnapshot)},
+#endif
+
     // NOTE: Adding a new flag requires adding a corresponding entry to enum
     // "LoginCustomFlags" in tools/metrics/histograms/enums.xml. See "Flag
     // Histograms" in tools/metrics/histograms/README.md (run the