[Suggested files] Enable drive zero state provider

This CL replaces the DriveQuickAccessProvider with the new
DriveZeroStateProvider, and adds a deprecation todo to the former.

If there are any issues with the new provider, this one CL can be
reverted to disable the entire feature.

Bug: 1034842
Change-Id: I6a82a948aa41301918d8a80368bfb5cda2303a11
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2437996Reviewed-by: Rachel Wong <wrong@chromium.org>
Commit-Queue: Tony Yeoman <tby@chromium.org>
Cr-Commit-Position: refs/heads/master@{#812497}

chrome/browser/ui/app_list/search/drive_quick_access_provider.h

@@ -25,6 +25,10 @@ class SearchController;
 
 // DriveQuickAccessProvider dispatches queries to extensions and fetches the
 // results from them via chrome.launcherSearchProvider API.
+//
+// TODO(crbug.com/1034842): This is deprecated in favour of
+// DriveZeroStateProvider. This class and related results classes can be
+// deleted.
 class DriveQuickAccessProvider : public SearchProvider,
                                  public drive::DriveIntegrationServiceObserver {
  public:

chrome/browser/ui/app_list/search/search_controller_factory.cc

@@ -63,7 +63,7 @@ constexpr size_t kMaxLauncherSearchResults = 4;
 // We need twice as many ZeroState and Drive file results as we need
 // duplicates of these results for the suggestion chips.
 constexpr size_t kMaxZeroStateFileResults = 20;
-constexpr size_t kMaxDriveQuickAccessResults = 10;
+constexpr size_t kMaxDriveZeroStateResults = 10;
 constexpr size_t kMaxAppReinstallSearchResults = 1;
 // We show up to 6 Play Store results. However, part of Play Store results may
 // be filtered out because they may correspond to already installed Web apps. So
@@ -86,13 +86,6 @@ constexpr size_t kMaxAssistantTextResults = 1;
 // TODO(wutao): Need UX spec.
 constexpr size_t kMaxSettingsShortcutResults = 6;
 
-// A flag to easily replace the old Drive zero-state provider with the new one
-// during development.
-//
-// TODO(crbug.com/1034842): Once implementation is finished, remove this flag
-// and always use the new provider.
-constexpr bool kUseNewDriveProvider = false;
-
 }  // namespace
 
 std::unique_ptr<SearchController> CreateSearchController(
@@ -200,21 +193,14 @@ std::unique_ptr<SearchController> CreateSearchController(
         controller->AddGroup(kMaxZeroStateFileResults);
     controller->AddProvider(zero_state_files_group_id,
                             std::make_unique<ZeroStateFileProvider>(profile));
-    size_t drive_quick_access_group_id =
-        controller->AddGroup(kMaxDriveQuickAccessResults);
-
-    if (kUseNewDriveProvider) {
-      controller->AddProvider(
-          drive_quick_access_group_id,
-          std::make_unique<DriveZeroStateProvider>(
-              profile, controller.get(),
-              content::BrowserContext::GetDefaultStoragePartition(profile)
-                  ->GetURLLoaderFactoryForBrowserProcess()));
-    } else {
-      controller->AddProvider(drive_quick_access_group_id,
-                              std::make_unique<DriveQuickAccessProvider>(
-                                  profile, controller.get()));
-    }
+    size_t drive_zero_state_group_id =
+        controller->AddGroup(kMaxDriveZeroStateResults);
+    controller->AddProvider(
+        drive_zero_state_group_id,
+        std::make_unique<DriveZeroStateProvider>(
+            profile, controller.get(),
+            content::BrowserContext::GetDefaultStoragePartition(profile)
+                ->GetURLLoaderFactoryForBrowserProcess()));
   }
 
   if (app_list_features::IsLauncherSettingsSearchEnabled()) {