Add support to previews/ for Server LoFi and LitePages

chrome/browser/previews/previews_service.cc

 // 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.
 
 #include "chrome/browser/previews/previews_service.h"
 
 #include "base/bind.h"
 #include "base/files/file_path.h"
 #include "base/memory/ptr_util.h"
 #include "base/sequenced_task_runner.h"
 #include "base/threading/sequenced_worker_pool.h"
 #include "chrome/common/chrome_constants.h"
+#include "components/data_reduction_proxy/core/common/data_reduction_proxy_params.h"
 #include "components/previews/core/previews_experiments.h"
 #include "components/previews/core/previews_io_data.h"
 #include "components/previews/core/previews_opt_out_store.h"
 #include "components/previews/core/previews_opt_out_store_sql.h"
 #include "components/previews/core/previews_ui_service.h"
 #include "content/public/browser/browser_thread.h"
 
 namespace {
 
 // Returns true if previews can be shown for |type|.
 bool IsPreviewsTypeEnabled(previews::PreviewsType type) {
   switch (type) {
     case previews::PreviewsType::OFFLINE:
       return previews::params::IsOfflinePreviewsEnabled();
     case previews::PreviewsType::CLIENT_LOFI:
       return previews::params::IsClientLoFiEnabled();
+    case previews::PreviewsType::SERVER_LOFI:
+      return data_reduction_proxy::params::IsLoFiOnViaFlags() ||
+             data_reduction_proxy::params::IsIncludedInLoFiEnabledFieldTrial();
+    case previews::PreviewsType::LITE_PAGE:
+      return (data_reduction_proxy::params::IsLoFiOnViaFlags() &&
+              data_reduction_proxy::params::AreLitePagesEnabledViaFlags()) ||
+             data_reduction_proxy::params::IsIncludedInLitePageFieldTrial();
+    // List remaining enum cases vs. default to catch when new one is added.

[tbansal1, 2017/05/02 21:49:30]

nit: I do not think this comment is needed since it is pretty common pattern in
switch case (probably it's also a part of the style guide).

[RyanSturm, 2017/05/02 22:57:18]

Done.

     case previews::PreviewsType::NONE:
     case previews::PreviewsType::LAST:
       break;
   }
   NOTREACHED();
   return false;
 }
 
 // Returns the version of preview treatment |type|. Defaults to 0 if not
 // specified in field trial config.
 int GetPreviewsTypeVersion(previews::PreviewsType type) {
   switch (type) {
     case previews::PreviewsType::OFFLINE:
       return previews::params::OfflinePreviewsVersion();
     case previews::PreviewsType::CLIENT_LOFI:
       return previews::params::ClientLoFiVersion();
+    case previews::PreviewsType::LITE_PAGE:
+      return data_reduction_proxy::params::LitePageVersion();
+    case previews::PreviewsType::SERVER_LOFI:
+      return data_reduction_proxy::params::LoFiVersion();
+    // List remaining enum cases vs. default to catch when new one is added.
     case previews::PreviewsType::NONE:
     case previews::PreviewsType::LAST:
       break;
   }
   NOTREACHED();
   return -1;
 }
 
 // Returns the enabled PreviewsTypes with their version.
 std::unique_ptr<previews::PreviewsTypeList> GetEnabledPreviews() {
@@ skipping 33 matching lines @@
       blocking_pool->GetSequencedTaskRunner(blocking_pool->GetSequenceToken());
 
   previews_ui_service_ = base::MakeUnique<previews::PreviewsUIService>(
       previews_io_data, io_task_runner,
       base::MakeUnique<previews::PreviewsOptOutStoreSQL>(
           io_task_runner, background_task_runner,
           profile_path.Append(chrome::kPreviewsOptOutDBFilename),
           GetEnabledPreviews()),
       base::Bind(&IsPreviewsTypeEnabled));
 }