Reland of Moving previews code from components/ to chrome/

components/previews/core/previews_experiments.cc

Index: components/previews/core/previews_experiments.cc
diff --git a/components/previews/core/previews_experiments.cc b/components/previews/core/previews_experiments.cc
index 77b973a2da62fdec35f3d677bf22d50c40105690..7b6d539b578f833ba15ab75f23b632a8cc4bc877 100644
--- a/components/previews/core/previews_experiments.cc
+++ b/components/previews/core/previews_experiments.cc
@@ -189,6 +189,19 @@ net::EffectiveConnectionType EffectiveConnectionTypeThreshold() {
   return effective_connection_type;
 }
 
+bool IsOfflinePreviewsEnabled() {
+  //  Check if "show_offline_pages" is set to "true".
+  return ClientSidePreviewsParamValue(kOfflinePagesSlowNetwork) ==
+         kExperimentEnabled;
+}
+
+int OfflinePreviewsVersion() {
+  int version;
+  if (!base::StringToInt(ClientSidePreviewsParamValue(kVersion), &version))
+    version = 0;
+  return version;
+}
+
 }  // namespace params
 
 bool IsIncludedInClientSidePreviewsExperimentsFieldTrial() {
@@ -200,47 +213,6 @@ bool IsIncludedInClientSidePreviewsExperimentsFieldTrial() {
       kEnabled, base::CompareCase::SENSITIVE);
 }
 
-bool IsPreviewsTypeEnabled(PreviewsType type) {
-  switch (type) {
-    case PreviewsType::OFFLINE:
-      return ClientSidePreviewsParamValue(kOfflinePagesSlowNetwork) ==
-             kExperimentEnabled;
-    default:
-      NOTREACHED();
-      return false;
-  }
-}
-
-int GetPreviewsTypeVersion(PreviewsType type) {
-  int version = 0;  // default
-  switch (type) {
-    case PreviewsType::OFFLINE:
-      base::StringToInt(ClientSidePreviewsParamValue(kVersion), &version);
-      return version;
-    // List remaining enum cases vs. default to catch when new one is added.
-    case PreviewsType::NONE:
-      break;
-    case PreviewsType::LAST:
-      break;
-  }
-  NOTREACHED();
-  return -1;
-}
-
-std::unique_ptr<PreviewsTypeList> GetEnabledPreviews() {
-  std::unique_ptr<PreviewsTypeList> enabled_previews(new PreviewsTypeList());
-
-  // Loop across all previews types (relies on sequential enum values).
-  for (int i = static_cast<int>(PreviewsType::NONE) + 1;
-       i < static_cast<int>(PreviewsType::LAST); ++i) {
-    PreviewsType type = static_cast<PreviewsType>(i);
-    if (IsPreviewsTypeEnabled(type)) {
-      enabled_previews->push_back({type, GetPreviewsTypeVersion(type)});
-    }
-  }
-  return enabled_previews;
-}
-
 bool EnableOfflinePreviewsForTesting() {
   std::map<std::string, std::string> params;
   params[kOfflinePagesSlowNetwork] = kExperimentEnabled;