optimization_guide: Correct remaining SEQUENCE_CHECKER errors.

HintsChecker::sequence_checker_ is made effective, which may cause the
checker to discover previously unknown sequence bugs if any exist.

class contains no non-const data or any other apparent reason to require
a sequence checker.

DecisionTreePredictionModel: :sequence_checker_ is removed, since that
Change-Id: I4c62720d62e2cbb32ea45acfcd9f482406361f14
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2606130
Commit-Queue: Jeremy Roman <jbroman@chromium.org>
Reviewed-by: Sophie Chang <sophiechang@chromium.org>
Cr-Commit-Position: refs/heads/master@{#840419}

components/optimization_guide/decision_tree_prediction_model.cc

@@ -121,8 +121,6 @@ bool DecisionTreePredictionModel::ValidateTreeNode(
 OptimizationTargetDecision DecisionTreePredictionModel::Predict(
     const base::flat_map<std::string, float>& model_features,
     double* prediction_score) {
-  SEQUENCE_CHECKER(sequence_checker_);
-
   *prediction_score = 0.0;
   // TODO(mcrouse): Add metrics to record if the model evaluation fails.
   if (!EvaluateModel(model_, model_features, prediction_score))

components/optimization_guide/decision_tree_prediction_model.h

@@ -11,7 +11,6 @@
 #include "base/containers/flat_map.h"
 #include "base/containers/flat_set.h"
 #include "base/macros.h"
-#include "base/sequence_checker.h"
 #include "components/optimization_guide/prediction_model.h"
 #include "components/optimization_guide/proto/models.pb.h"
 
@@ -90,8 +89,6 @@ class DecisionTreePredictionModel : public PredictionModel {
                         const proto::TreeNode& node,
                         int node_index) const;
 
-  SEQUENCE_CHECKER(sequence_checker_);
-
   DISALLOW_COPY_AND_ASSIGN(DecisionTreePredictionModel);
 };
 

components/optimization_guide/hints_fetcher.cc

@@ -151,7 +151,7 @@ bool HintsFetcher::FetchOptimizationGuideServiceHints(
         optimization_types,
     optimization_guide::proto::RequestContext request_context,
     HintsFetchedCallback hints_fetched_callback) {
-  SEQUENCE_CHECKER(sequence_checker_);
+  DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
   DCHECK_GT(optimization_types.size(), 0u);
 
   if (content::GetNetworkConnectionTracker()->IsOffline()) {
@@ -286,7 +286,7 @@ bool HintsFetcher::FetchOptimizationGuideServiceHints(
 void HintsFetcher::HandleResponse(const std::string& get_hints_response_data,
                                   int net_status,
                                   int response_code) {
-  SEQUENCE_CHECKER(sequence_checker_);
+  DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
 
   std::unique_ptr<proto::GetHintsResponse> get_hints_response =
       std::make_unique<proto::GetHintsResponse>();
@@ -390,7 +390,7 @@ void HintsFetcher::UpdateHostsSuccessfullyFetched(
 // Callback is only invoked if |active_url_loader_| is bound and still alive.
 void HintsFetcher::OnURLLoadComplete(
     std::unique_ptr<std::string> response_body) {
-  SEQUENCE_CHECKER(sequence_checker_);
+  DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
 
   int response_code = -1;
   if (active_url_loader_->ResponseInfo() &&
@@ -408,7 +408,7 @@ void HintsFetcher::OnURLLoadComplete(
 
 std::vector<std::string> HintsFetcher::GetSizeLimitedHostsDueForHintsRefresh(
     const std::vector<std::string>& hosts) const {
-  SEQUENCE_CHECKER(sequence_checker_);
+  DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
 
   DictionaryPrefUpdate hosts_fetched(
       pref_service_, prefs::kHintsFetcherHostsSuccessfullyFetched);