Adapt diff tests after FileInfoJson started using experiment features

With change Iba17d4c46, FileInfoJson was switched to run the new diff
cache using Gerrit's experiments instead of configs in project.config.
We forgot to adapt the tests in RevisionDiffNewDiffCacheIT to use the
new flags, hence doing it in this change to make the tests actually run
in new diff cache mode.

Change-Id: I6df0470c79234f23366cc5043ac7e0e88edbe409
diff --git a/java/com/google/gerrit/server/change/FileInfoJsonExperimentImpl.java b/java/com/google/gerrit/server/change/FileInfoJsonExperimentImpl.java
index 3f7ce68..81f014d 100644
--- a/java/com/google/gerrit/server/change/FileInfoJsonExperimentImpl.java
+++ b/java/com/google/gerrit/server/change/FileInfoJsonExperimentImpl.java
@@ -14,6 +14,7 @@
 
 package com.google.gerrit.server.change;
 
+import com.google.common.annotations.VisibleForTesting;
 import com.google.gerrit.common.Nullable;
 import com.google.gerrit.entities.Change;
 import com.google.gerrit.entities.PatchSet;
@@ -33,7 +34,9 @@
  * FileInfoJsonNewImpl}.
  */
 public class FileInfoJsonExperimentImpl implements FileInfoJson {
-  private final String NEW_DIFF_CACHE_FEATURE = "GerritBackendRequestFeature__use_new_diff_cache";
+  @VisibleForTesting
+  public static final String NEW_DIFF_CACHE_FEATURE =
+      "GerritBackendRequestFeature__use_new_diff_cache";
 
   private final FileInfoJsonOldImpl oldImpl;
   private final FileInfoJsonNewImpl newImpl;
diff --git a/javatests/com/google/gerrit/acceptance/api/revision/RevisionDiffIT.java b/javatests/com/google/gerrit/acceptance/api/revision/RevisionDiffIT.java
index d8dab33..f1a8f18 100644
--- a/javatests/com/google/gerrit/acceptance/api/revision/RevisionDiffIT.java
+++ b/javatests/com/google/gerrit/acceptance/api/revision/RevisionDiffIT.java
@@ -50,6 +50,7 @@
 import com.google.gerrit.extensions.restapi.BadRequestException;
 import com.google.gerrit.extensions.restapi.BinaryResult;
 import com.google.gerrit.extensions.webui.EditWebLink;
+import com.google.gerrit.server.change.FileInfoJsonExperimentImpl;
 import com.google.gerrit.server.patch.DiffOperations;
 import com.google.gerrit.server.patch.filediff.FileDiffOutput;
 import com.google.inject.Inject;
@@ -109,7 +110,8 @@
 
     intraline = baseConfig.getBoolean(TEST_PARAMETER_MARKER, "intraline", false);
     useNewDiffCacheListFiles =
-        baseConfig.getBoolean("cache", "diff_cache", "runNewDiffCache_ListFiles", false);
+        Arrays.asList(baseConfig.getStringList("experiments", null, "enabled"))
+            .contains(FileInfoJsonExperimentImpl.NEW_DIFF_CACHE_FEATURE);
     useNewDiffCacheGetDiff =
         baseConfig.getBoolean("cache", "diff_cache", "runNewDiffCache_GetDiff", false);
 
diff --git a/javatests/com/google/gerrit/acceptance/api/revision/RevisionNewDiffCacheIT.java b/javatests/com/google/gerrit/acceptance/api/revision/RevisionNewDiffCacheIT.java
index ec0bcc6..714bd78 100644
--- a/javatests/com/google/gerrit/acceptance/api/revision/RevisionNewDiffCacheIT.java
+++ b/javatests/com/google/gerrit/acceptance/api/revision/RevisionNewDiffCacheIT.java
@@ -14,6 +14,7 @@
 
 package com.google.gerrit.acceptance.api.revision;
 
+import com.google.gerrit.server.change.FileInfoJsonExperimentImpl;
 import com.google.gerrit.testing.ConfigSuite;
 import org.eclipse.jgit.lib.Config;
 
@@ -26,7 +27,8 @@
   @ConfigSuite.Default
   public static Config newDiffCacheConfig() {
     Config config = new Config();
-    config.setBoolean("cache", "diff_cache", "runNewDiffCache_ListFiles", true);
+    config.setString(
+        "experiments", null, "enabled", FileInfoJsonExperimentImpl.NEW_DIFF_CACHE_FEATURE);
     return config;
   }
 }