[Feed] Adding flag combinations to include undoable actions.

Bug: 1020661
Change-Id: I720511c79c6a161352223c8a7b610806af0f177f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1895169Reviewed-by: Dan H <harringtond@chromium.org>
Commit-Queue: Jonathan Freed <freedjm@chromium.org>
Cr-Commit-Position: refs/heads/master@{#711927}

chrome/browser/about_flags.cc

@@ -603,6 +603,19 @@ const FeatureEntry::FeatureParam
     kInterestFeedLargeImagesAndSnippetsFeatureVariationConstant[] = {
         {"feed_ui_enabled", "true"},
         {"snippets_enabled", "true"}};
+const FeatureEntry::FeatureParam
+    kInterestFeedLargerImagesWithUndoableActionsFeatureVariationConstant[] = {
+        {"feed_ui_enabled", "true"},
+        {"undoable_actions_enabled", "true"}};
+const FeatureEntry::FeatureParam
+    kInterestFeedSnippetsWithUndoableActionsFeatureVariationConstant[] = {
+        {"snippets_enabled", "true"},
+        {"undoable_actions_enabled", "true"}};
+const FeatureEntry::FeatureParam
+    kInterestFeedLargeImagesAndSnippetsWithUndoableActionsFeatureVariationConstant
+        [] = {{"feed_ui_enabled", "true"},
+              {"snippets_enabled", "true"},
+              {"undoable_actions_enabled", "true"}};
 const FeatureEntry::FeatureVariation kInterestFeedFeatureVariations[] = {
     {"(larger images)", kInterestFeedLargerImagesFeatureVariationConstant,
      base::size(kInterestFeedLargerImagesFeatureVariationConstant), nullptr},
@@ -611,6 +624,21 @@ const FeatureEntry::FeatureVariation kInterestFeedFeatureVariations[] = {
     {"(larger images and snippets)",
      kInterestFeedLargeImagesAndSnippetsFeatureVariationConstant,
      base::size(kInterestFeedLargeImagesAndSnippetsFeatureVariationConstant),
+     nullptr},
+    {"(larger images w/ undoable actions)",
+     kInterestFeedLargerImagesWithUndoableActionsFeatureVariationConstant,
+     base::size(
+         kInterestFeedLargerImagesWithUndoableActionsFeatureVariationConstant),
+     nullptr},
+    {"(snippets w/ undoable actions)",
+     kInterestFeedSnippetsWithUndoableActionsFeatureVariationConstant,
+     base::size(
+         kInterestFeedSnippetsWithUndoableActionsFeatureVariationConstant),
+     nullptr},
+    {"(larger images and snippets w/ undoable actions)",
+     kInterestFeedLargeImagesAndSnippetsWithUndoableActionsFeatureVariationConstant,
+     base::size(
+         kInterestFeedLargeImagesAndSnippetsWithUndoableActionsFeatureVariationConstant),
      nullptr}};
 
 const FeatureEntry::FeatureVariation kRemoteSuggestionsFeatureVariations[] = {