🏠 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 becb9cd64f61ec286f4c03d8b006ad4625547f89..dd6f3a3deb59d8ebcd34ee5fb4839fed89f0683a 100644
--- a/chrome/browser/android/chrome_feature_list.cc
+++ b/chrome/browser/android/chrome_feature_list.cc
@@ -52,6 +52,7 @@ const base::Feature* kFeaturesExposedToJava[] = {
     &kCCTExternalLinkHandling,
     &kCCTPostMessageAPI,
     &kChromeHomeFeature,
+    &kChromeHomeExpandButton,
     &kContentSuggestionsSettings,
     &kContextualSearchSingleActions,
     &kContextualSearchUrlActions,
@@ -124,6 +125,9 @@ 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};