[Chromecast] Add a reboot reason for anomaly detector

Bug: internal b/189446805
Test: local build
Change-Id: Ia2da33bccb36fd6cd0159953216af912b62e55d6
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3192884
Reviewed-by: Luke Halliwell <halliwell@chromium.org>
Commit-Queue: Yuqi Sun <sunyq@google.com>
Cr-Commit-Position: refs/heads/main@{#927584}

chromecast/public/reboot_shlib.h

@@ -103,6 +103,11 @@ class CHROMECAST_EXPORT RebootShlib {
     // risky to attempt without a full process restart. Very few experiments
     // trigger this path.
     EXPERIMENT_CHANGE = 19,
+
+    // A reboot is triggered when the anomaly detection service detects a
+    // system-level anomaly and needs to recover from it with restarting the
+    // Cast component.
+    ANOMALY = 20,
   };
 
   // Initializes any platform-specific reboot systems.

chromecast/system/reboot/reboot_util_core.cc

@@ -48,6 +48,7 @@ bool RebootUtil::IsValidRebootSource(RebootShlib::RebootSource reboot_source) {
     case RebootShlib::RebootSource::MULTI_SERVICE_BUG:
     case RebootShlib::RebootSource::POWER_MANAGER_SHUTDOWN:
     case RebootShlib::RebootSource::EXPERIMENT_CHANGE:
+    case RebootShlib::RebootSource::ANOMALY:
       return true;
     default:
       return false;