[Home] Update flag description for enabling Chrome Home

BUG=713928
TBR=mdjones@chromium.org

Change-Id: I69e4fb6bdac3c06a114a807f98411b67143ae965
Reviewed-on: https://chromium-review.googlesource.com/567525Reviewed-by: Theresa <twellington@chromium.org>
Commit-Queue: Theresa <twellington@chromium.org>
Cr-Commit-Position: refs/heads/master@{#485808}

chrome/browser/flag_descriptions.cc

@@ -2013,7 +2013,9 @@ const char kReaderModeHeuristicsAlwaysOn[] = "Always";
 
 const char kChromeHomeName[] = "Chrome Home";
 
-const char kChromeHomeDescription[] = "Enables Chrome Home on Android.";
+const char kChromeHomeDescription[] =
+    "Enables Chrome Home on Android. You must restart the browser"
+    " twice for changes to take effect.";
 
 const char kChromeHomeExpandButtonName[] = "Chrome Home Expand Button";