Add flag "update-hover-at-begin-frame" to about://flags

Add flag "update-hover-at-begin-frame" to about://flags so that this
flag is easy to turn on and off by users.

Bug: 877132
Change-Id: I03f7d007f6576659ffdfdf6c221204fea8c76c48
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1715394
Commit-Queue: Lan Wei <[email protected]>
Reviewed-by: David Bokan <[email protected]>
Cr-Commit-Position: refs/heads/master@{#680995}
diff --git a/chrome/browser/about_flags.cc b/chrome/browser/about_flags.cc
index c9f8ac4..d3127292 100644
--- a/chrome/browser/about_flags.cc
+++ b/chrome/browser/about_flags.cc
@@ -4208,6 +4208,11 @@
      flag_descriptions::kNotificationSchedulerDebugOptionDescription,
      kOsAndroid, MULTI_VALUE_TYPE(kNotificationSchedulerChoices)},
 
+    {"update-hover-at-begin-frame",
+     flag_descriptions::kUpdateHoverAtBeginFrameName,
+     flag_descriptions::kUpdateHoverAtBeginFrameDescription, kOsAll,
+     FEATURE_VALUE_TYPE(features::kUpdateHoverAtBeginFrame)},
+
     // 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