arc: Make Play Store item persistance in shelf.

chrome/browser/ui/ash/chrome_launcher_prefs.cc

Index: chrome/browser/ui/ash/chrome_launcher_prefs.cc
diff --git a/chrome/browser/ui/ash/chrome_launcher_prefs.cc b/chrome/browser/ui/ash/chrome_launcher_prefs.cc
index 53a4f3a7348122247be30a2ef2c13b92225d416b..f50f138bbd8e2fc30d1e90db43beb7b0d6524e22 100644
--- a/chrome/browser/ui/ash/chrome_launcher_prefs.cc
+++ b/chrome/browser/ui/ash/chrome_launcher_prefs.cc
@@ -12,6 +12,7 @@
 #include "base/strings/string_number_conversions.h"
 #include "base/values.h"
 #include "chrome/browser/app_mode/app_mode_utils.h"
+#include "chrome/browser/chromeos/arc/arc_support_host.h"
 #include "chrome/browser/ui/ash/launcher/launcher_controller_helper.h"
 #include "chrome/common/extensions/extension_constants.h"
 #include "chrome/common/pref_names.h"
@@ -325,6 +326,8 @@ std::vector<std::string> GetPinnedAppsFromPrefs(
     }
   }
 
+  apps.push_back(ArcSupportHost::kHostAppId);
+
   // If not added yet, the chrome item will be the last item in the list.
   if (!chrome_listed)
     apps.push_back(extension_misc::kChromeAppId);