🏠 Add expand button and flag to enable it

chrome/browser/android/chrome_feature_list.cc

Index: chrome/browser/android/chrome_feature_list.cc
diff --git a/chrome/browser/android/chrome_feature_list.cc b/chrome/browser/android/chrome_feature_list.cc
index b14be19d26caf48389716662214bf2a157282ce1..39e3dff0c179008af32ff7afc9557d9b40e54150 100644
--- a/chrome/browser/android/chrome_feature_list.cc
+++ b/chrome/browser/android/chrome_feature_list.cc
@@ -51,6 +51,7 @@ const base::Feature* kFeaturesExposedToJava[] = {
     &kCCTExternalLinkHandling,
     &kCCTPostMessageAPI,
     &kChromeHomeFeature,
+    &kChromeHomeExpandButton,
     &kContentSuggestionsSettings,
     &kContextualSearchSingleActions,
     &kContextualSearchUrlActions,
@@ -125,6 +126,9 @@ const base::Feature kCCTPostMessageAPI{"CCTPostMessageAPI",
 const base::Feature kChromeHomeFeature{"ChromeHome",
                                        base::FEATURE_DISABLED_BY_DEFAULT};
 
+const base::Feature kChromeHomeExpandButton{"ChromeHomeExpandButton",
+                                            base::FEATURE_DISABLED_BY_DEFAULT};
+
 const base::Feature kContentSuggestionsSettings{
     "ContentSuggestionsSettings", base::FEATURE_DISABLED_BY_DEFAULT};