Add support to previews/ for Server LoFi and LitePages

components/previews/core/previews_experiments.h

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef COMPONENTS_PREVIEWS_CORE_PREVIEWS_EXPERIMENTS_H_
 #define COMPONENTS_PREVIEWS_CORE_PREVIEWS_EXPERIMENTS_H_
 
+#include <string>
 #include <utility>
 #include <vector>
 
 #include "base/time/time.h"
 #include "net/nqe/effective_connection_type.h"
 
 namespace previews {
 
 namespace params {
 
@@ skipping 24 matching lines @@
 
 // The amount of time after any opt out that no previews should be shown.
 base::TimeDelta SingleOptOutDuration();
 
 // The amount of time that an offline page is considered fresh enough to be
 // shown as a preview.
 base::TimeDelta OfflinePreviewFreshnessDuration();
 
 // The threshold of EffectiveConnectionType above which offline previews should
 // not be served.
-net::EffectiveConnectionType EffectiveConnectionTypeThresholdForOffline();
+net::EffectiveConnectionType EffectiveConnectionTypeThreshold();

[tbansal1, 2017/05/05 20:34:39]

why rename this? As per the comment above, seems like this is specific for
offline previews.

[RyanSturm, 2017/05/05 20:51:35]

Done.

 
 // Whether offline previews are enabled.
 bool IsOfflinePreviewsEnabled();
 
 // The blacklist version for offline previews.
 int OfflinePreviewsVersion();
 
 // Whether Client LoFi previews are enabled.
 bool IsClientLoFiEnabled();
 
 // The blacklist version for Client LoFi previews.
 int ClientLoFiVersion();
 
 // The threshold of EffectiveConnectionType above which Client LoFi previews
 // should not be served.
 net::EffectiveConnectionType EffectiveConnectionTypeThresholdForClientLoFi();
 
 }  // namespace params
 
 enum class PreviewsType {
   NONE = 0,
 
   // The user is shown an offline page as a preview.
   OFFLINE = 1,
 
-  // Replace images with placeholders generated on the client.
-  CLIENT_LOFI = 2,
+  // Replace images with placeholders.
+  LOFI = 2,
+
+  // The user is shown a server lite page.
+  LITE_PAGE = 3,
 
   // Insert new enum values here. Keep values sequential to allow looping
   // from NONE+1 to LAST-1.
-  LAST = 3,
+  LAST = 4,
 };
 
 typedef std::vector<std::pair<PreviewsType, int>> PreviewsTypeList;
 
+// Gets the string representation of |type|.
+std::string GetStringNameForType(PreviewsType type);
+
 }  // namespace previews
 
 #endif  // COMPONENTS_PREVIEWS_CORE_PREVIEWS_EXPERIMENTS_H_