Add enable-offlining-recent-pages feature switch. The feature is not yet implemented. See launch bug below for description.

BUG=587599

Review URL: https://codereview.chromium.org/1750883002

Cr-Commit-Position: refs/heads/master@{#379997}

4 files changed, 37 insertions, 8 deletions

diff --git a/components/offline_pages/BUILD.gn b/components/offline_pages/BUILD.gn
index cdbdb7b..1c2efd1 100644
--- a/components/offline_pages/BUILD.gn
+++ b/components/offline_pages/BUILD.gn
@@ -74,6 +74,7 @@ source_set("unit_tests") {
 
   deps = [
     ":offline_pages",
+    ":switches",
     ":test_support",
     "//base",
     "//base/test:test_support",
diff --git a/components/offline_pages/offline_page_feature.cc b/components/offline_pages/offline_page_feature.cc
index ed390b8..ab00925 100644
--- a/components/offline_pages/offline_page_feature.cc
+++ b/components/offline_pages/offline_page_feature.cc
@@ -7,14 +7,13 @@
 #include <string>
 
 #include "base/command_line.h"
+#include "base/feature_list.h"
 #include "base/metrics/field_trial.h"
 #include "base/strings/string_util.h"
 #include "build/build_config.h"
 #include "components/offline_pages/offline_page_switches.h"
 #include "components/version_info/version_info.h"
 
-#if defined(OS_ANDROID)
-
 namespace offline_pages {
 
 namespace {
@@ -26,6 +25,10 @@ const char kEnabledAsBookmarksGroupName[] = "EnabledAsBookmarks";
 const char kEnabledAsSavedPagesGroupName[] = "EnabledAsSavedPages";
 }  // namespace
 
+const base::Feature kOffliningRecentPagesFeature {
+   "offline-recent-pages", base::FEATURE_DISABLED_BY_DEFAULT
+};
+
 FeatureMode GetOfflinePageFeatureMode() {
   // Note: It's important to query the field trial state first, to ensure that
   // UMA reports the correct group.
@@ -75,6 +78,9 @@ bool IsOfflinePagesEnabled() {
          mode == FeatureMode::ENABLED_AS_SAVED_PAGES;
 }
 
-}  // namespace offline_pages
+bool IsOffliningRecentPagesEnabled() {
+  return  base::FeatureList::IsEnabled(kOffliningRecentPagesFeature) &&
+          IsOfflinePagesEnabled();
+}
 
-#endif
+}  // namespace offline_pages
diff --git a/components/offline_pages/offline_page_feature.h b/components/offline_pages/offline_page_feature.h
index 600140f..1d01a2d 100644
--- a/components/offline_pages/offline_page_feature.h
+++ b/components/offline_pages/offline_page_feature.h
@@ -5,12 +5,13 @@
 #ifndef COMPONENTS_OFFLINE_PAGES_OFFLINE_PAGE_FEATURE_H_
 #define COMPONENTS_OFFLINE_PAGES_OFFLINE_PAGE_FEATURE_H_
 
+#include "base/feature_list.h"
 #include "build/build_config.h"
 
-#if defined(OS_ANDROID)
-
 namespace offline_pages {
 
+extern const base::Feature kOffliningRecentPagesFeature;
+
 // GENERATED_JAVA_ENUM_PACKAGE: org.chromium.components.offlinepages
 enum class FeatureMode {
   // Offline pages feature is disabled.
@@ -27,8 +28,9 @@ FeatureMode GetOfflinePageFeatureMode();
 // Returns true if offline pages is enabled.
 bool IsOfflinePagesEnabled();
 
-}  // namespace offline_pages
+// Returns true if offlining of recent pages (aka 'Last N pages') is enabled.
+bool IsOffliningRecentPagesEnabled();
 
-#endif  // defined(OS_ANDROID)
+}  // namespace offline_pages
 
 #endif  // COMPONENTS_OFFLINE_PAGES_OFFLINE_PAGE_FEATURE_H_
diff --git a/components/offline_pages/offline_page_model_unittest.cc b/components/offline_pages/offline_page_model_unittest.cc
index aea301e..31b3723 100644
--- a/components/offline_pages/offline_page_model_unittest.cc
+++ b/components/offline_pages/offline_page_model_unittest.cc
@@ -9,6 +9,8 @@
 #include <utility>
 
 #include "base/bind.h"
+#include "base/command_line.h"
+#include "base/feature_list.h"
 #include "base/files/file_util.h"
 #include "base/files/scoped_temp_dir.h"
 #include "base/run_loop.h"
@@ -25,7 +27,9 @@
 #include "components/bookmarks/browser/bookmark_undo_delegate.h"
 #include "components/bookmarks/browser/bookmark_undo_provider.h"
 #include "components/bookmarks/test/test_bookmark_client.h"
+#include "components/offline_pages/offline_page_feature.h"
 #include "components/offline_pages/offline_page_item.h"
+#include "components/offline_pages/offline_page_switches.h"
 #include "components/offline_pages/offline_page_test_archiver.h"
 #include "components/offline_pages/offline_page_test_store.h"
 #include "testing/gtest/include/gtest/gtest.h"
@@ -989,4 +993,20 @@ TEST_F(OfflinePageModelTest, SaveRetrieveMultipleClientIds) {
   EXPECT_TRUE(id_set.find(offline2) != id_set.end());
 }
 
+TEST(CommandLineFlagsTest, OffliningRecentPages) {
+  // TODO(dimich): once offline pages are enabled by default, remove this.
+  base::CommandLine::ForCurrentProcess()->AppendSwitch(
+      switches::kEnableOfflinePages);
+  // Disabled by default.
+  EXPECT_FALSE(offline_pages::IsOffliningRecentPagesEnabled());
+
+  // Check if feature is correctly enabled by command-line flag.
+  base::FeatureList::ClearInstanceForTesting();
+  scoped_ptr<base::FeatureList> feature_list(new base::FeatureList);
+  feature_list->InitializeFromCommandLine(
+      offline_pages::kOffliningRecentPagesFeature.name, "");
+  base::FeatureList::SetInstance(std::move(feature_list));
+  EXPECT_TRUE(offline_pages::IsOffliningRecentPagesEnabled());
+}
+
 }  // namespace offline_pages