DeviceStatusCollector: add ProbeError to BacklightInfo request

Update cros_healthd telemetry handling code to check for and log errors
from BacklightInfo request.

Bug: chromium:1041153
Change-Id: I445a014fad10b452b393d61c022561dede092005
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2148126Reviewed-by: Paul Moy <pmoy@chromium.org>
Reviewed-by: Jorge Lucangeli Obes <jorgelo@chromium.org>
Reviewed-by: Maksim Ivanov <emaxx@chromium.org>
Commit-Queue: Trent Begin <tbegin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#759311}

chrome/browser/chromeos/policy/status_collector/device_status_collector.cc

@@ -927,9 +927,14 @@ class DeviceStatusCollectorState : public StatusCollectorState {
         }
       }
 
-      const auto& backlight_info = probe_result->backlight_info;
-      if (backlight_info.has_value()) {
-        for (const auto& backlight : backlight_info.value()) {
+      // Process BacklightResult.
+      const auto& backlight_result = probe_result->backlight_result;
+      if (!backlight_result.is_null()) {
+        if (backlight_result->is_error()) {
+          LOG(ERROR) << "cros_healthd: Error getting backlight info: "
+                     << backlight_result->get_error()->msg;
+        } else {
+          for (const auto& backlight : backlight_result->get_backlight_info()) {
             em::BacklightInfo* const backlight_info_out =
                 response_params_.device_status->add_backlight_info();
             backlight_info_out->set_path(backlight->path);
@@ -937,6 +942,7 @@ class DeviceStatusCollectorState : public StatusCollectorState {
             backlight_info_out->set_brightness(backlight->brightness);
           }
         }
+      }
 
       // Process FanResult.
       const auto& fan_result = probe_result->fan_result;

chrome/browser/chromeos/policy/status_collector/device_status_collector_browsertest.cc

@@ -493,6 +493,9 @@ void GetFakeCrosHealthdData(
   chromeos::cros_healthd::mojom::BacklightInfo backlight_info(
       kFakeBacklightPath, kFakeMaxBrightness, kFakeBrightness);
   backlight_vector.push_back(backlight_info.Clone());
+  auto backlight_result =
+      chromeos::cros_healthd::mojom::BacklightResult::NewBacklightInfo(
+          std::move(backlight_vector));
   std::vector<chromeos::cros_healthd::mojom::FanInfoPtr> fan_vector;
   chromeos::cros_healthd::mojom::FanInfo fan_info(kFakeSpeedRpm);
   fan_vector.push_back(fan_info.Clone());
@@ -502,7 +505,7 @@ void GetFakeCrosHealthdData(
       battery_info.Clone(), std::move(block_device_info),
       cached_vpd_info.Clone(), std::move(cpu_result),
       std::move(timezone_result), std::move(memory_result),
-      std::move(backlight_vector), std::move(fan_result));
+      std::move(backlight_result), std::move(fan_result));
 
   // Create fake SampledData.
   em::CPUTempInfo fake_cpu_temp_sample;

chromeos/services/cros_healthd/public/cpp/service_connection_unittest.cc

@@ -129,13 +129,13 @@ mojom::MemoryResultPtr MakeMemoryResult() {
       43264 /* page_faults_since_last_boot */));
 }
 
-base::Optional<std::vector<mojom::BacklightInfoPtr>> MakeBacklightInfo() {
+mojom::BacklightResultPtr MakeBacklightResult() {
   std::vector<mojom::BacklightInfoPtr> backlight_info;
   backlight_info.push_back(mojom::BacklightInfo::New(
       "path_1" /* path */, 6537 /* max_brightness */, 987 /* brightness */));
   backlight_info.push_back(mojom::BacklightInfo::New(
       "path_2" /* path */, 3242 /* max_brightness */, 65 /* brightness */));
-  return backlight_info;
+  return mojom::BacklightResult::NewBacklightInfo(std::move(backlight_info));
 }
 
 mojom::FanResultPtr MakeFanResult() {
@@ -152,7 +152,8 @@ mojom::TelemetryInfoPtr MakeTelemetryInfo() {
       MakeCachedVpdInfo() /* vpd_info */, MakeCpuResult() /* cpu_result */,
       MakeTimezoneResult() /* timezone_result */,
       MakeMemoryResult() /* memory_result */,
-      MakeBacklightInfo() /* backlight_info */, MakeFanResult() /* fan_result */
+      MakeBacklightResult() /* backlight_result */,
+      MakeFanResult() /* fan_result */
   );
 }
 

chromeos/services/cros_healthd/public/mojom/cros_healthd_probe.mojom

@@ -171,6 +171,15 @@ struct MemoryInfo {
   uint32 page_faults_since_last_boot;
 };
 
+// Backlight probe result. Can either be populated with the BacklightInfo or an
+// error retrieving the information.
+union BacklightResult {
+  // Valid BacklightInfo.
+  array<BacklightInfo> backlight_info;
+  // The error that occurred attempting to retrieve the BacklightInfo.
+  ProbeError error;
+};
+
 // Backlight information.
 struct BacklightInfo {
   // Path to this backlight on the system. Useful if the caller needs to
@@ -226,7 +235,7 @@ struct TelemetryInfo {
   MemoryResult? memory_result;
   // Information about all of the device's backlights. Only present when
   // kBacklight was included in the categories input to ProbeTelemetryInfo.
-  array<BacklightInfo>? backlight_info;
+  BacklightResult? backlight_result;
   // Information about each of the device's fans. Only present when kFan was
   // included in the categories input to ProbeTelemetryInfo.
   FanResult? fan_result;