Add feature flag: PhoneHubRecentApps

This flag to Enables the Recent Apps feature in Phone Hub, which
allows users to relaunch the streamed app.

Bug: b/190466630
Test: Pass AboutFlagsHistogramTest.
Change-Id: Iedb3862584747e3eadc5cac326bf1929f77fbea6
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2983086
Auto-Submit: Paulz Chen <[email protected]>
Reviewed-by: Ryan Hansberry <[email protected]>
Commit-Queue: Paulz Chen <[email protected]>
Cr-Commit-Position: refs/heads/master@{#900716}
diff --git a/chrome/browser/flag_descriptions.cc b/chrome/browser/flag_descriptions.cc
index fecc01c..ca6b625 100644
--- a/chrome/browser/flag_descriptions.cc
+++ b/chrome/browser/flag_descriptions.cc
@@ -4938,6 +4938,11 @@
     "Enables the Camera Roll feature in Phone Hub, which allows users to "
     "access recent photos and videos taken on a connected Android device.";
 
+const char kPhoneHubRecentAppsName[] = "Recent Apps in Phone Hub";
+const char kPhoneHubRecentAppsDescription[] =
+    "Enables the Recent Apps feature in Phone Hub, which allows users to "
+    "relaunch a recently streamed app.";
+
 const char kReduceDisplayNotificationsName[] = "Reduce display notifications";
 const char kReduceDisplayNotificationsDescription[] =
     "If enabled, notifications for display rotation, display removed, display "