Added flag for alternate launcher settings (remaining changes to come).

chrome/browser/about_flags.cc

Index: chrome/browser/about_flags.cc
diff --git a/chrome/browser/about_flags.cc b/chrome/browser/about_flags.cc
index a723e2ee6997d428b34053a5155217a12f79241d..1d9924b5c4096e1d77e65f69bf7e37fad5117594 100644
--- a/chrome/browser/about_flags.cc
+++ b/chrome/browser/about_flags.cc
@@ -906,6 +906,13 @@ const Experiment kExperiments[] = {
   },
 #if defined(OS_CHROMEOS)
   {
+      "ash-use-alt-shelf",
+      IDS_FLAGS_ALTERNATE_SHELF_LAYOUT_NAME,
+      IDS_FLAGS_ALTERNATE_SHELF_LAYOUT_DESCRIPTION,
+      kOsCrOS,
+      SINGLE_VALUE_TYPE(ash::switches::kAshUseAlternateShelfLayout)
+  },
+  {
     "enable-background-loader",
     IDS_ENABLE_BACKLOADER_NAME,
     IDS_ENABLE_BACKLOADER_DESCRIPTION,