Add support to previews/ for Server LoFi and LitePages

components/previews/core/previews_io_data_unittest.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 "components/previews/core/previews_io_data.h"
 
 #include <initializer_list>
 #include <map>
 #include <memory>
 #include <string>
@@ skipping 28 matching lines @@
 namespace previews {
 
 namespace {
 
 // TODO(sclittle): Tests should be testing the actual prod code that checks if
 // the appropriate field trial is enabled for the preview, instead of testing
 // this function here. Consider moving that code out of
 // chrome/browser/previews/previews_service.cc and into the previews/ component.
 bool IsPreviewFieldTrialEnabled(PreviewsType type) {
   switch (type) {
+    // Use the offline field trial to simulate LoFi and LitePages being enabled.

[tbansal1, 2017/05/02 21:49:31]

Is it possible to expand on this comment a bit? This is a bit confusing (why is
LoFi/Lite using offline field trial).

[RyanSturm, 2017/05/02 22:57:19]

Done. I removed sclittle's comment as it makes little sense to try to remove a
layering abstraction in test. Using the field trials is syntactically easy, but
this check could be replaced with any other bool that controls the flow of this
method for the purpose of the test.

     case PreviewsType::OFFLINE:
+    case PreviewsType::LITE_PAGE:
+    case PreviewsType::SERVER_LOFI:
       return params::IsOfflinePreviewsEnabled();
     case PreviewsType::CLIENT_LOFI:
       return params::IsClientLoFiEnabled();
     case PreviewsType::NONE:
     case PreviewsType::LAST:
       break;
   }
   NOTREACHED();
   return false;
 }
@@ skipping 206 matching lines @@
 
   base::HistogramTester histogram_tester;
   EXPECT_FALSE(
       io_data()->ShouldAllowPreview(*CreateRequest(), PreviewsType::OFFLINE));
   histogram_tester.ExpectUniqueSample(
       "Previews.EligibilityReason.Offline",
       static_cast<int>(PreviewsEligibilityReason::NETWORK_QUALITY_UNAVAILABLE),
       1);
 }
 
+TEST_F(PreviewsIODataTest, TestAllowLoFiLitePageWhenNetworkQualityFast) {
+  // LoFi and LitePage check NQE on their own.
+  InitializeUIService();
+  CreateFieldTrialWithParams("ClientSidePreviews", "Enabled",
+                             {{"show_offline_pages", "true"},
+                              {"max_allowed_effective_connection_type", "2G"}});
+
+  network_quality_estimator()->set_effective_connection_type(
+      net::EFFECTIVE_CONNECTION_TYPE_3G);
+
+  base::HistogramTester histogram_tester;
+  EXPECT_TRUE(io_data()->ShouldAllowPreview(*CreateRequest(),
+                                            PreviewsType::SERVER_LOFI));
+  EXPECT_TRUE(
+      io_data()->ShouldAllowPreview(*CreateRequest(), PreviewsType::LITE_PAGE));
+  histogram_tester.ExpectUniqueSample(
+      "Previews.EligibilityReason.ServerLoFi",
+      static_cast<int>(PreviewsEligibilityReason::ALLOWED), 1);
+  histogram_tester.ExpectUniqueSample(
+      "Previews.EligibilityReason.LitePage",
+      static_cast<int>(PreviewsEligibilityReason::ALLOWED), 1);
+}
+
 TEST_F(PreviewsIODataTest, TestDisallowOfflineWhenNetworkQualityFast) {
   InitializeUIService();
   CreateFieldTrialWithParams("ClientSidePreviews", "Enabled",
                              {{"show_offline_pages", "true"},
                               {"max_allowed_effective_connection_type", "2G"}});
 
   network_quality_estimator()->set_effective_connection_type(
       net::EFFECTIVE_CONNECTION_TYPE_3G);
 
   base::HistogramTester histogram_tester;
@@ skipping 13 matching lines @@
   network_quality_estimator()->set_effective_connection_type(
       net::EFFECTIVE_CONNECTION_TYPE_2G);
 
   std::unique_ptr<net::URLRequest> request = CreateRequest();
   request->SetLoadFlags(net::LOAD_BYPASS_CACHE);
 
   base::HistogramTester histogram_tester;
   EXPECT_FALSE(io_data()->ShouldAllowPreview(*request, PreviewsType::OFFLINE));
   histogram_tester.ExpectUniqueSample(
       "Previews.EligibilityReason.Offline",
-      static_cast<int>(
-          PreviewsEligibilityReason::RELOAD_DISALLOWED_FOR_OFFLINE),
-      1);
+      static_cast<int>(PreviewsEligibilityReason::RELOAD_DISALLOWED), 1);
 }
 
 TEST_F(PreviewsIODataTest, TestAllowOffline) {
   InitializeUIService();
   CreateFieldTrialWithParams("ClientSidePreviews", "Enabled",
                              {{"show_offline_pages", "true"},
                               {"max_allowed_effective_connection_type", "2G"}});
 
   network_quality_estimator()->set_effective_connection_type(
       net::EFFECTIVE_CONNECTION_TYPE_2G);
@@ skipping 88 matching lines @@
   EXPECT_TRUE(
       io_data()->ShouldAllowPreview(*request, PreviewsType::CLIENT_LOFI));
   histogram_tester.ExpectUniqueSample(
       "Previews.EligibilityReason.ClientLoFi",
       static_cast<int>(PreviewsEligibilityReason::ALLOWED), 1);
 }
 
 }  // namespace
 
 }  // namespace previews