remove LogAndMaybeSortLifecycleUnitWithTabRanker.

LogAndMaybeSortLifecycleUnitWithTabRanker is not used and will not be used in any time soon. So remove it from TabManagerDelegate for now.

Bug: 1131349
Change-Id: I614336b9ddfe4758d1a364a39195070dde237a79
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2423800Reviewed-by: François Doray <fdoray@chromium.org>
Reviewed-by: Charles . <charleszhao@chromium.org>
Reviewed-by: Thanh Nguyen <thanhdng@chromium.org>
Reviewed-by: Sébastien Marchand <sebmarchand@chromium.org>
Commit-Queue: Charles . <charleszhao@chromium.org>
Cr-Commit-Position: refs/heads/master@{#810475}

chrome/browser/resource_coordinator/tab_manager_delegate_chromeos.cc

@@ -28,7 +28,6 @@
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/memory/memory_kills_monitor.h"
 #include "chrome/browser/resource_coordinator/lifecycle_unit.h"
-#include "chrome/browser/resource_coordinator/tab_activity_watcher.h"
 #include "chrome/browser/resource_coordinator/tab_lifecycle_unit_external.h"
 #include "chrome/browser/resource_coordinator/tab_manager_stats_collector.h"
 #include "chrome/browser/resource_coordinator/utils.h"
@@ -527,46 +526,6 @@ TabManagerDelegate::GetSortedCandidates(
   return candidates;
 }
 
-void TabManagerDelegate::LogAndMaybeSortLifecycleUnitWithTabRanker(
-    std::vector<Candidate>* candidates,
-    LifecycleUnitSorter sorter) {
-  const uint32_t num_of_tab_to_score = GetNumOldestTabsToScoreWithTabRanker();
-  if (num_of_tab_to_score <= 1)
-    return;
-
-  const ProcessType process_type =
-      static_cast<ProcessType>(GetProcessTypeToScoreWithTabRanker());
-
-  // Put the oldest num_of_tab_to_score lifecycle units into a vector.
-  LifecycleUnitVector oldest_lifecycle_units;
-  for (auto it = candidates->rbegin(); it != candidates->rend(); ++it) {
-    auto& candidate = *it;
-    if (oldest_lifecycle_units.size() == num_of_tab_to_score ||
-        candidate.process_type() < process_type)
-      break;
-    if (candidate.lifecycle_unit()) {
-      oldest_lifecycle_units.push_back(candidate.lifecycle_unit());
-    }
-  }
-
-  // log and possibly Re-sort them with TabRanker.
-  std::move(sorter).Run(&oldest_lifecycle_units);
-
-  if (base::FeatureList::IsEnabled(features::kTabRanker)) {
-    // Put the sorted lifecycle units back to their original vacancies.
-    for (auto it = candidates->rbegin(); it != candidates->rend(); ++it) {
-      const auto& candidate = *it;
-      if (oldest_lifecycle_units.empty() ||
-          candidate.process_type() < process_type)
-        break;
-      if (candidate.lifecycle_unit()) {
-        *it = Candidate(oldest_lifecycle_units.back());
-        oldest_lifecycle_units.pop_back();
-      }
-    }
-  }
-}
-
 bool TabManagerDelegate::IsRecentlyKilledArcProcess(
     const std::string& process_name,
     const TimeTicks& now) {
@@ -617,14 +576,6 @@ void TabManagerDelegate::LowMemoryKillImpl(
   std::vector<Candidate> candidates =
       GetSortedCandidates(GetLifecycleUnits(), arc_processes);
 
-  // Log and Re-order oldest N LifecycleUnits if TabRanker is enabled; otherwise
-  // only log N LifecycleUnits and the candidates will be unchanged.
-  LogAndMaybeSortLifecycleUnitWithTabRanker(
-      &candidates,
-      base::BindOnce(
-          &TabActivityWatcher::LogAndMaybeSortLifecycleUnitWithTabRanker,
-          base::Unretained(TabActivityWatcher::GetInstance())));
-
   // TODO(semenzato): decide if TargetMemoryToFreeKB is doing real
   // I/O and if it is, move to I/O thread (crbug.com/778703).
   int target_memory_to_free_kb = 0;

chrome/browser/resource_coordinator/tab_manager_delegate_chromeos.h

@@ -147,18 +147,6 @@ class TabManagerDelegate : public wm::ActivationChangeObserver,
       const LifecycleUnitVector& lifecycle_units,
       const OptionalArcProcessList& arc_processes);
 
-  // This is only used for TabRanker experiment for now.
-  // If TabRanker is enabled, this will take the last N lifecycle units in the
-  // |candidates|; sort these lifecycle units based on the TabRanker order; and
-  // put these sorted lifecycle unit back to the vacancies of these lifecycle
-  // units in the |candidates|.
-  // If TabRanker is disabled, this will log the TabMetrics of these lifecycle
-  // units.
-  // All apps in the |candidates| will not be influenced.
-  static void LogAndMaybeSortLifecycleUnitWithTabRanker(
-      std::vector<Candidate>* candidates,
-      LifecycleUnitSorter sorter);
-
   // Returns the LifecycleUnits in TabManager. Virtual for unit tests.
   virtual LifecycleUnitVector GetLifecycleUnits();
 

chrome/browser/resource_coordinator/tab_manager_delegate_chromeos_unittest.cc

@@ -106,74 +106,6 @@ TEST_F(TabManagerDelegateTest, CandidatesSortedWithFocusedAppAndTab) {
   EXPECT_EQ("focused", candidates[1].app()->process_name());
 }
 
-// Test to make sure old process types are active when TabRanker experiment
-// is turned on.
-TEST_F(TabManagerDelegateTest, SortLifecycleUnitWithTabRanker) {
-  base::test::ScopedFeatureList feature_list;
-  feature_list.InitAndEnableFeatureWithParameters(
-      features::kTabRanker,
-      {{"number_of_oldest_tabs_to_score_with_TabRanker", "20"},
-       {"process_type_of_tabs_to_score_with_TabRanker", "4"}});
-  std::vector<arc::ArcProcess> arc_processes;
-  arc_processes.emplace_back(1, 10, "focused", arc::mojom::ProcessState::TOP,
-                             kIsFocused, 99);
-  arc_processes.emplace_back(2, 20, "visible1", arc::mojom::ProcessState::TOP,
-                             kNotFocused, 89);
-  arc_processes.emplace_back(
-      3, 30, "service", arc::mojom::ProcessState::SERVICE, kNotFocused, 95);
-
-  TestLifecycleUnit tab1(
-      base::TimeTicks() + base::TimeDelta::FromMilliseconds(100), 4);
-  TestLifecycleUnit tab2(
-      base::TimeTicks() + base::TimeDelta::FromMilliseconds(90), 5, false);
-  TestLifecycleUnit tab3(
-      base::TimeTicks() + base::TimeDelta::FromMilliseconds(80), 6);
-  LifecycleUnitVector lifecycle_units{&tab1, &tab2, &tab3};
-
-  TabManagerDelegate::OptionalArcProcessList opt_arc_processes(
-      std::move(arc_processes));
-  std::vector<TabManagerDelegate::Candidate> candidates;
-  candidates = TabManagerDelegate::GetSortedCandidates(lifecycle_units,
-                                                       opt_arc_processes);
-  // Verify the original order.
-  ASSERT_EQ(6U, candidates.size());
-
-  EXPECT_EQ("focused", candidates[0].app()->process_name());
-  EXPECT_EQ(ProcessType::FOCUSED_APP, candidates[0].process_type());
-
-  EXPECT_EQ(&tab2, candidates[1].lifecycle_unit());
-  EXPECT_EQ(ProcessType::PROTECTED_BACKGROUND, candidates[1].process_type());
-
-  EXPECT_EQ("visible1", candidates[2].app()->process_name());
-  EXPECT_EQ(ProcessType::PROTECTED_BACKGROUND, candidates[2].process_type());
-
-  EXPECT_EQ(&tab1, candidates[3].lifecycle_unit());
-  EXPECT_EQ(ProcessType::BACKGROUND, candidates[3].process_type());
-
-  EXPECT_EQ("service", candidates[4].app()->process_name());
-  EXPECT_EQ(ProcessType::BACKGROUND, candidates[4].process_type());
-
-  EXPECT_EQ(&tab3, candidates[5].lifecycle_unit());
-  EXPECT_EQ(ProcessType::BACKGROUND, candidates[5].process_type());
-
-  auto oldest_first = [](LifecycleUnitVector* lifecycle_units) {
-    std::sort(lifecycle_units->begin(), lifecycle_units->end(),
-              [](LifecycleUnit* a, LifecycleUnit* b) {
-                return a->GetLastFocusedTime() < b->GetLastFocusedTime();
-              });
-  };
-
-  // Verify the re-ranked order.
-  TabManagerDelegate::LogAndMaybeSortLifecycleUnitWithTabRanker(
-      &candidates, base::BindOnce(oldest_first));
-  EXPECT_EQ("focused", candidates[0].app()->process_name());
-  EXPECT_EQ(&tab2, candidates[1].lifecycle_unit());
-  EXPECT_EQ("visible1", candidates[2].app()->process_name());
-  EXPECT_EQ(&tab3, candidates[3].lifecycle_unit());
-  EXPECT_EQ("service", candidates[4].app()->process_name());
-  EXPECT_EQ(&tab1, candidates[5].lifecycle_unit());
-}
-
 class MockTabManagerDelegate : public TabManagerDelegate {
  public:
   MockTabManagerDelegate()