[Webapps] Add switch to about: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 4110765ba4e9743076c6bf85ac3621a19c1947df..3a7c1d756961812e05621e3e12932138e7a06d47 100644
--- a/chrome/common/chrome_switches.cc
+++ b/chrome/common/chrome_switches.cc
@@ -1484,6 +1484,9 @@ const char kEnableSpdyProxyAuth[]           = "enable-spdy-proxy-auth";
 const char kEnableAccessibilityTabSwitcher[] =
     "enable-accessibility-tab-switcher";
 
+// Makes the "Add to Homescreen" shortcut visible.
+const char kEnableAddToHomescreen[]         = "enable-add-to-homescreen";
+
 // Enables the new NTP.
 const char kEnableNewNTP[]                  = "enable-new-ntp";