Moving previews code from components/ to chrome/

chrome/browser/previews/previews_service.cc

Index: chrome/browser/previews/previews_service.cc
diff --git a/chrome/browser/previews/previews_service.cc b/chrome/browser/previews/previews_service.cc
index bfc31eaa413f45c50099d837c54aab0ec5c4a08c..a0375e5f8833c32f8b2d615610ebdcf4e32b4689 100644
--- a/chrome/browser/previews/previews_service.cc
+++ b/chrome/browser/previews/previews_service.cc
@@ -4,17 +4,65 @@
 
 #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/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::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::NONE:
+    case previews::PreviewsType::LAST:
+      break;
+  }
+  NOTREACHED();
+  return -1;
+}
+
+// Returns the enabled PreviewsTypes with their version.
+std::unique_ptr<previews::PreviewsTypeList> GetEnabledPreviews() {
+  std::unique_ptr<previews::PreviewsTypeList> enabled_previews(
+      new previews::PreviewsTypeList());
+
+  // Loop across all previews types (relies on sequential enum values).
+  for (int i = static_cast<int>(previews::PreviewsType::NONE) + 1;
+       i < static_cast<int>(previews::PreviewsType::LAST); ++i) {
+    previews::PreviewsType type = static_cast<previews::PreviewsType>(i);
+    if (IsPreviewsTypeEnabled(type))
+      enabled_previews->push_back({type, GetPreviewsTypeVersion(type)});
+  }
+  return enabled_previews;
+}
+
+}  // namespace
+
 PreviewsService::PreviewsService() {
   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
 }
@@ -39,5 +87,7 @@ void PreviewsService::Initialize(
       previews_io_data, io_task_runner,
       base::MakeUnique<previews::PreviewsOptOutStoreSQL>(
           io_task_runner, background_task_runner,
-          profile_path.Append(chrome::kPreviewsOptOutDBFilename)));
+          profile_path.Append(chrome::kPreviewsOptOutDBFilename),
+          GetEnabledPreviews()),
+      base::Bind(&IsPreviewsTypeEnabled));
 }