[Power ML] Change UserActivityPrediction flag to enabled

Bug: 862461
Change-Id: I624d39293e50754629b3b30990828af73f57f0b3
Reviewed-on: https://chromium-review.googlesource.com/c/1482281Reviewed-by: Dan Erat <derat@chromium.org>
Reviewed-by: Steven Holte <holte@chromium.org>
Commit-Queue: Jia Meng <jiameng@chromium.org>
Cr-Commit-Position: refs/heads/master@{#634856}

chrome/browser/chromeos/power/ml/smart_dim/model_impl.cc

@@ -222,25 +222,18 @@ void LogPowerMLSmartDimParameterResult(SmartDimParameterResult result) {
   UMA_HISTOGRAM_ENUMERATION("PowerML.SmartDimParameter.Result", result);
 }
 
-// Returns "dim_threshold" from experiment parameter. Also logs status to UMA
-// (i.e. whether the parameter is undefined or cannot be parsed, or can be
-// parsed successfully.
-base::Optional<float> GetDimThreshold() {
-  const std::string dim_threshold_str = base::GetFieldTrialParamValueByFeature(
-      features::kUserActivityPrediction, "dim_threshold");
-  if (dim_threshold_str.empty()) {
-    LogPowerMLSmartDimParameterResult(SmartDimParameterResult::kUndefinedError);
-    return base::nullopt;
-  }
-
-  double dim_threshold_double;
-  if (!base::StringToDouble(dim_threshold_str, &dim_threshold_double)) {
-    LogPowerMLSmartDimParameterResult(SmartDimParameterResult::kParsingError);
-    return base::nullopt;
+// Returns "dim_threshold" from experiment parameter. Also logs status to UMA.
+float GetDimThreshold() {
+  const double default_threshold = -0.18;
+  const double dim_threshold = base::GetFieldTrialParamByFeatureAsDouble(
+      features::kUserActivityPrediction, "dim_threshold", default_threshold);
+  if (std::abs(dim_threshold - default_threshold) < 1e-10) {
+    LogPowerMLSmartDimParameterResult(
+        SmartDimParameterResult::kUseDefaultValue);
+  } else {
+    LogPowerMLSmartDimParameterResult(SmartDimParameterResult::kSuccess);
   }
-
-  LogPowerMLSmartDimParameterResult(SmartDimParameterResult::kSuccess);
-  return base::Optional<float>(dim_threshold_double);
+  return dim_threshold;
 }
 
 }  // namespace
@@ -322,12 +315,12 @@ SmartDimModelResult SmartDimModelImpl::CalculateInactivityScoreTfNative(
 UserActivityEvent::ModelPrediction
 SmartDimModelImpl::CreatePredictionFromInactivityScore(float inactivity_score) {
   UserActivityEvent::ModelPrediction prediction;
-  const base::Optional<float> dim_threshold = GetDimThreshold();
+  const float dim_threshold = GetDimThreshold();
 
-  prediction.set_decision_threshold(ScoreToProbability(dim_threshold.value()));
+  prediction.set_decision_threshold(ScoreToProbability(dim_threshold));
   prediction.set_inactivity_score(ScoreToProbability(inactivity_score));
 
-  if (inactivity_score >= dim_threshold.value()) {
+  if (inactivity_score >= dim_threshold) {
     prediction.set_response(UserActivityEvent::ModelPrediction::DIM);
   } else {
     prediction.set_response(UserActivityEvent::ModelPrediction::NO_DIM);
@@ -342,11 +335,6 @@ UserActivityEvent::ModelPrediction SmartDimModelImpl::ShouldDimTfNative(
   UserActivityEvent::ModelPrediction prediction;
   prediction.set_response(UserActivityEvent::ModelPrediction::MODEL_ERROR);
 
-  const base::Optional<float> dim_threshold = GetDimThreshold();
-  if (!dim_threshold) {
-    return prediction;
-  }
-
   float inactivity_score = 0;
   const SmartDimModelResult result =
       CalculateInactivityScoreTfNative(input_features, &inactivity_score);
@@ -368,12 +356,6 @@ void SmartDimModelImpl::ShouldDimMlService(
   UserActivityEvent::ModelPrediction prediction;
   prediction.set_response(UserActivityEvent::ModelPrediction::MODEL_ERROR);
 
-  const base::Optional<float> dim_threshold = GetDimThreshold();
-  if (!dim_threshold) {
-    std::move(callback).Run(prediction);
-    return;
-  }
-
   std::vector<float> vectorized_features;
   auto preprocess_result =
       PreprocessInput(input_features, &vectorized_features);

chrome/browser/chromeos/power/ml/smart_dim/model_impl.h

@@ -44,7 +44,8 @@ enum class SmartDimParameterResult {
   kSuccess = 0,
   kUndefinedError = 1,
   kParsingError = 2,
-  kMaxValue = kParsingError
+  kUseDefaultValue = 3,
+  kMaxValue = kUseDefaultValue
 };
 
 // Real implementation of SmartDimModel that predicts whether an upcoming screen

chrome/browser/chromeos/power/ml/smart_dim/model_unittest.cc

@@ -146,25 +146,6 @@ TEST_F(SmartDimModelImplTest, ShouldDim) {
   EXPECT_TRUE(callback_done);
 }
 
-TEST_F(SmartDimModelImplTest, ModelError) {
-  // Model parameter is undefined, which would trigger a model error.
-  bool callback_done = false;
-  smart_dim_model_.RequestDimDecision(
-      features_, base::BindOnce(
-                     [](bool* callback_done,
-                        UserActivityEvent::ModelPrediction prediction) {
-                       EXPECT_EQ(
-                           UserActivityEvent::ModelPrediction::MODEL_ERROR,
-                           prediction.response());
-                       EXPECT_FALSE(prediction.has_decision_threshold());
-                       EXPECT_FALSE(prediction.has_inactivity_score());
-                       *callback_done = true;
-                     },
-                     &callback_done));
-  scoped_task_environment_.RunUntilIdle();
-  EXPECT_TRUE(callback_done);
-}
-
 // Check that CancelableCallback ensures a callback doesn't execute twice, in
 // case two RequestDimDecision() calls were made before any callback ran.
 TEST_F(SmartDimModelImplTest, CheckCancelableCallback) {

chromeos/constants/chromeos_features.cc

@@ -80,7 +80,7 @@ const base::Feature kUseMessagesStagingUrl{"UseMessagesStagingUrl",
 // Defined here rather than in //chrome alongside other related features so that
 // PowerPolicyController can check it.
 const base::Feature kUserActivityPrediction{"UserActivityPrediction",
-                                            base::FEATURE_DISABLED_BY_DEFAULT};
+                                            base::FEATURE_ENABLED_BY_DEFAULT};
 
 // Enables or disables ML service inferencing (instead of TFNative inferencing)
 // for the Smart Dim feature on Chrome OS.

tools/metrics/histograms/enums.xml

@@ -43316,6 +43316,10 @@ Called by update_net_trust_anchors.py.-->
   <int value="2" label="Parsing error">
     Threshold parameter was not parsed correctly from string to double.
   </int>
+  <int value="3" label="Use default value">
+    Threshold parameter was not supplied or same as the default value. In either
+    case, the default value was used.
+  </int>
 </enum>
 
 <enum name="PowerSupplyType">