[Hashed logging] Delete all metric provider logic

The metrics provider class is going to be almost completely rewritten
for the framework. It will make future CLs cleaner to start at a blank
slate.

Bug: 1016655
Change-Id: Ib0e02d7632df11b01167a566db4eac4cbda6acab
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1903107Reviewed-by: Thanh Nguyen <thanhdng@chromium.org>
Commit-Queue: Tony Yeoman <tby@chromium.org>
Cr-Commit-Position: refs/heads/master@{#713627}

chrome/browser/ui/app_list/search/search_result_ranker/app_list_launch_metrics_provider.h

@@ -25,14 +25,7 @@ class ChromeMetricsServiceClient;
 
 namespace app_list {
 
-// Stores a user's random secret. This struct exists to make clear at the type
-// system level what is a secret and what isn't.
-struct Secret {
-  std::string value;
-};
-
 class AppListLaunchMetricsProviderTest;
-class AppListLaunchRecorderStateProto;
 
 // AppListLaunchMetricsProvider is responsible for filling out the
 // |app_list_launch_event| section of the UMA proto. This class should not be
@@ -51,76 +44,28 @@ class AppListLaunchMetricsProvider : public metrics::MetricsProvider {
  private:
   friend class ::ChromeMetricsServiceClient;
   friend class app_list::AppListLaunchMetricsProviderTest;
-  FRIEND_TEST_ALL_PREFIXES(AppListLaunchMetricsProviderTest, EventsAreCapped);
-
-  // Filename for the the state proto within the user's home directory. This is
-  // just the basename, not the full path.
-  static char kStateProtoFilename[];
 
   // Beyond this number of OnAppListLaunch calls between successive calls to
   // ProvideCurrentSessionData, we stop logging.
   static int kMaxEventsPerUpload;
 
-  enum class InitState { UNINITIALIZED, INIT_STARTED, ENABLED, DISABLED };
-
   // The constructors are private so that this class can only be instantied by
-  // ChromeMetricsServiceClient and tests. The class has two constructors so
-  // that the tests can override the profile dir.
+  // ChromeMetricsServiceClient and tests.
   AppListLaunchMetricsProvider();
 
-  AppListLaunchMetricsProvider(
-      base::RepeatingCallback<base::Optional<base::FilePath>()>
-          get_profile_dir_callback);
-
   // Records the information in |launch_info|, to be converted into a hashed
   // form and logged to UMA. Actual logging occurs periodically, so it is not
   // guaranteed that any call to this method will be logged.
   //
-  // OnAppListLaunch should only be called from the browser thread, after it has
-  // finished initializing.
+  // OnAppListLaunch should only be called from the browser UI sequence.
   void OnAppListLaunch(const AppListLaunchRecorder::LaunchInfo& launch_info);
 
-  // Starts initialization if needed. This involves reading the secret from
-  // disk.
+  // Performs initialization once a user has logged in.
   void Initialize();
 
-  // Populates this object's internal state from the given state |proto|, and
-  // finishes initialisation. This is called by Initialize() and passed the
-  // state proto that has been loaded from disk, if it exists. OnStateLoaded may
-  // write a new proto to disk if, for example, the given |proto| is invalid.
-  void OnStateLoaded(
-      const base::FilePath& proto_filepath,
-      const base::Optional<AppListLaunchRecorderStateProto>& proto);
-
-  // Converts |launch_info| into a hashed |event| proto ready for logging.
-  void CreateLaunchEvent(const AppListLaunchRecorder::LaunchInfo& launch_info,
-                         metrics::ChromeOSAppListLaunchEventProto* event);
-
-  // A function that returns the directory of the current profile. This is a
-  // callback so that it can be faked out for testing.
-  const base::RepeatingCallback<base::Optional<base::FilePath>()>
-      get_profile_dir_callback_;
-
   // Subscription for receiving logging event callbacks from HashedLogger.
   std::unique_ptr<AppListLaunchRecorder::LaunchEventSubscription> subscription_;
 
-  // Cache of input launch data, to be hashed and returned when
-  // ProvideCurrentSessionData() is called.
-  std::vector<AppListLaunchRecorder::LaunchInfo> launch_info_cache_;
-
-  // The initialization state of the AppListLaunchMetricsProvider. Events are
-  // only provided on a call to ProvideCurrentSessionData() once this is
-  // enabled, and nothing is recorded if this is disabled.
-  InitState init_state_;
-
-  // Secret per-user salt concatenated with values before hashing. Serialized
-  // to disk.
-  base::Optional<Secret> secret_;
-
-  // Per-user per-client ID used only for AppListLaunchMetricsProvider.
-  // Serialized to disk.
-  base::Optional<uint64_t> user_id_;
-
   SEQUENCE_CHECKER(sequence_checker_);
 
   base::WeakPtrFactory<AppListLaunchMetricsProvider> weak_factory_{this};