🏠 Add expand button and flag to enable it

chrome/browser/flag_descriptions.cc

Index: chrome/browser/flag_descriptions.cc
diff --git a/chrome/browser/flag_descriptions.cc b/chrome/browser/flag_descriptions.cc
index c4ad013c954efb75a193e589869a77b686df8135..8e9167a7eba83cec11c9636e9942818b4a7df84d 100644
--- a/chrome/browser/flag_descriptions.cc
+++ b/chrome/browser/flag_descriptions.cc
@@ -1973,6 +1973,11 @@ const char kChromeHomeName[] = "Chrome Home";
 
 const char kChromeHomeDescription[] = "Enables Chrome Home on Android.";
 
+const char kChromeHomeExpandButtonName[] = "Chrome Home Expand Button";
+
+const char kChromeHomeExpandButtonDescription[] =
+    "Enables the expand button for Chrome Home.";
+
 #endif  // defined(OS_ANDROID)
 
 //  In-Product Help flags