Revert "arc: Add ANR stats per period."

This reverts commit 5f0165a.

Reason for revert: See http://b/228557820. This is blocking LKGM - causes DCHECK for nonexistent pref.

Original change's description:
> arc: Add ANR stats per period.
>
> This adds ANR rate for starting period and ANR rate on regular basis
> taken each 4 hours. Starting period is 10 minutes after ARC start.
> Shorter sessions are ignored. Regular period is calculated based on ARC
> session activity and updated each 4-hours interval. It also supports
> ARC session restarts. That means if session is restarted in the middle
> of the period, it would be continued when user logs in the next time.
>
> BUG=b:225214120
> TEST=unit test
>
> Change-Id: I5fe522e4fcb051f06470f76969884aa4ff580be9
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3537585
> Reviewed-by: Muhammad Hasan Khan <mhasank@chromium.org>
> Reviewed-by: Yusuke Sato <yusukes@chromium.org>
> Commit-Queue: Yury Khmel <khmel@chromium.org>
> Cr-Commit-Position: refs/heads/main@{#988608}

Bug: b:225214120
Change-Id: Ib89397b8681686cc8e1e4cb4de25c890e2743116
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3578196
Reviewed-by: Hidehiko Abe <hidehiko@chromium.org>
Commit-Queue: Eliot Courtney <edcourtney@chromium.org>
Owners-Override: Eliot Courtney <edcourtney@chromium.org>
Cr-Commit-Position: refs/heads/main@{#990293}

ash/components/arc/BUILD.gn

@@ -66,8 +66,6 @@ static_library("arc") {
     "memory/arc_memory_bridge.h",
     "memory_pressure/arc_memory_pressure_bridge.cc",
     "memory_pressure/arc_memory_pressure_bridge.h",
-    "metrics/arc_metrics_anr.cc",
-    "metrics/arc_metrics_anr.h",
     "metrics/arc_metrics_service.cc",
     "metrics/arc_metrics_service.h",
     "metrics/stability_metrics_manager.cc",
@@ -400,7 +398,6 @@ source_set("unit_tests") {
     "media_session/arc_media_session_bridge_unittest.cc",
     "memory/arc_memory_bridge_unittest.cc",
     "memory_pressure/arc_memory_pressure_bridge_unittest.cc",
-    "metrics/arc_metrics_anr_unittest.cc",
     "metrics/arc_metrics_service_unittest.cc",
     "metrics/stability_metrics_manager_unittest.cc",
     "midis/arc_midis_bridge_unittest.cc",

ash/components/arc/arc_prefs.cc

@@ -120,15 +120,6 @@ const char kArcPlayStoreLaunchMetricCanBeRecorded[] =
     "arc.playstore_launched_by_user";
 
 // ======== LOCAL STATE PREFS ========
-// ANR count which is currently pending counted for ARC start, not flashed to
-// UMA.
-const char kAnrOnStartPendingCount[] = "arc.anr_pending_count_on_start";
-
-// ANR count which is currently pending, not flashed to UMA.
-const char kAnrPendingCount[] = "arc.anr_pending_count";
-
-// Keeps the duration of the current ANR rate period.
-const char kAnrPendingDuration[] = "arc.anr_pending_duration";
 
 // A boolean preference that indicates whether this device has run with the
 // native bridge 64 bit support experiment enabled. Persisting value in local
@@ -161,10 +152,6 @@ void RegisterLocalStatePrefs(PrefRegistrySimple* registry) {
   registry->RegisterBooleanPref(kNativeBridge64BitSupportExperimentEnabled,
                                 false);
   registry->RegisterDictionaryPref(kStabilityMetrics);
-
-  registry->RegisterIntegerPref(kAnrPendingCount, 0);
-  registry->RegisterIntegerPref(kAnrOnStartPendingCount, 0);
-  registry->RegisterTimeDeltaPref(kAnrPendingDuration, base::TimeDelta());
 }
 
 void RegisterProfilePrefs(PrefRegistrySimple* registry) {

ash/components/arc/arc_prefs.h

@@ -47,9 +47,6 @@ ARC_EXPORT extern const char kEngagementPrefsPrefix[];
 ARC_EXPORT extern const char kArcPlayStoreLaunchMetricCanBeRecorded[];
 
 // Local state prefs in lexicographical order.
-ARC_EXPORT extern const char kAnrOnStartPendingCount[];
-ARC_EXPORT extern const char kAnrPendingCount[];
-ARC_EXPORT extern const char kAnrPendingDuration[];
 ARC_EXPORT extern const char kArcSerialNumberSalt[];
 ARC_EXPORT extern const char kArcSnapshotHours[];
 ARC_EXPORT extern const char kArcSnapshotInfo[];