Add enable-app-shims to chrome://flags.

chrome/common/chrome_switches.cc

Index: chrome/common/chrome_switches.cc
diff --git a/chrome/common/chrome_switches.cc b/chrome/common/chrome_switches.cc
index 533511ae796233df973ac5912600ce78e772e491..8539d15efd27be05f929682506da32d46e2f10ee 100644
--- a/chrome/common/chrome_switches.cc
+++ b/chrome/common/chrome_switches.cc
@@ -1519,6 +1519,9 @@ const char kPasswordStore[]                 = "password-store";
 // if it does.
 const char kEnableAppListShim[]             = "enable-app-list-shim";
 
+// Enable to allow creation and launch of app shims for platform apps.
+const char kEnableAppShims[]                = "enable-app-shims";
+
 // Enables the tabs expose feature ( http://crbug.com/50307 ).
 const char kEnableExposeForTabs[]           = "enable-expose-for-tabs";