[Bluetooth] Add flag to enable bluetooth sessionized metrics

BUG=b:179805303

Change-Id: I80a50b9a353cc53c70238dc46ff35983baabd4d4
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2733649
Reviewed-by: Tony Yeoman <[email protected]>
Reviewed-by: Ryan Hansberry <[email protected]>
Commit-Queue: Yu Liu <[email protected]>
Cr-Commit-Position: refs/heads/master@{#862495}
diff --git a/chrome/browser/flag_descriptions.cc b/chrome/browser/flag_descriptions.cc
index e51c9183..9442edf 100644
--- a/chrome/browser/flag_descriptions.cc
+++ b/chrome/browser/flag_descriptions.cc
@@ -4717,6 +4717,11 @@
 const char kEnableBluetoothVerboseLogsForGooglersDescription[] =
     "Enables Bluetooth verbose logs for Googlers in feedback reports.";
 
+const char kBluetoothSessionizedMetricsName[] =
+    "Enable Bluetooth sessionized metrics";
+const char kBluetoothSessionizedMetricsDescription[] =
+    "Enables collecting and processing Bluetooth sessionized metrics.";
+
 const char kShowDateInTrayName[] = "Enable Show Date In Tray";
 const char kShowDateInTrayDescription[] =
     "Showing date in status area when the screen is sufficiently large.";