Drop the global memory state from memory coordinator

content/browser/memory/memory_state_updater.cc

Index: content/browser/memory/memory_state_updater.cc
diff --git a/content/browser/memory/memory_state_updater.cc b/content/browser/memory/memory_state_updater.cc
deleted file mode 100644
index a432fb3745ae57e861d369f71856e88e37f5fbd6..0000000000000000000000000000000000000000
--- a/content/browser/memory/memory_state_updater.cc
+++ /dev/null
@@ -1,182 +0,0 @@
-// Copyright 2016 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#include "content/browser/memory/memory_state_updater.h"
-
-#include "base/metrics/histogram_macros.h"
-#include "base/strings/string_number_conversions.h"
-#include "components/variations/variations_associated_data.h"
-#include "content/browser/memory/memory_monitor.h"
-
-namespace content {
-
-namespace {
-
-// A expected renderer size. These values come from the median of appropriate
-// UMA stats.
-#if defined(OS_ANDROID) || defined(OS_IOS)
-const int kDefaultExpectedRendererSizeMB = 40;
-#elif defined(OS_WIN)
-const int kDefaultExpectedRendererSizeMB = 70;
-#else // Mac, Linux, and ChromeOS
-const int kDefaultExpectedRendererSizeMB = 120;
-#endif
-
-// Default values for parameters to determine the global state.
-const int kDefaultNewRenderersUntilThrottled = 4;
-const int kDefaultNewRenderersUntilSuspended = 2;
-const int kDefaultNewRenderersBackToNormal = 5;
-const int kDefaultNewRenderersBackToThrottled = 3;
-const int kDefaultMinimumTransitionPeriodSeconds = 30;
-const int kDefaultMonitoringIntervalSeconds = 5;
-
-void SetIntVariationParameter(const std::map<std::string, std::string> params,
-                              const char* name,
-                              int* target) {
-  const auto& iter = params.find(name);
-  if (iter == params.end())
-    return;
-  int value;
-  if (!iter->second.empty() && base::StringToInt(iter->second, &value)) {
-    DCHECK(value > 0);
-    *target = value;
-  }
-}
-
-void SetSecondsVariationParameter(
-    const std::map<std::string, std::string> params,
-    const char* name,
-    base::TimeDelta* target) {
-  const auto& iter = params.find(name);
-  if (iter == params.end())
-    return;
-  int value;
-  if (!iter->second.empty() && base::StringToInt(iter->second, &value)) {
-    DCHECK(value > 0);
-    *target = base::TimeDelta::FromSeconds(value);
-  }
-}
-
-}  // namespace
-
-MemoryStateUpdater::MemoryStateUpdater(
-    MemoryCoordinatorImpl* coordinator,
-    scoped_refptr<base::SingleThreadTaskRunner> task_runner)
-    : coordinator_(coordinator), task_runner_(task_runner) {
-  DCHECK(coordinator_);
-  InitializeParameters();
-  DCHECK(ValidateParameters());
-}
-
-MemoryStateUpdater::~MemoryStateUpdater() {}
-
-base::MemoryState MemoryStateUpdater::CalculateNextState() {
-  using MemoryState = base::MemoryState;
-
-  int available =
-      coordinator_->memory_monitor()->GetFreeMemoryUntilCriticalMB();
-
-  // TODO(chrisha): Move this histogram recording to a better place when
-  // https://codereview.chromium.org/2479673002/ is landed.
-  UMA_HISTOGRAM_MEMORY_LARGE_MB("Memory.Coordinator.FreeMemoryUntilCritical",
-                                available);
-
-  if (available <= 0)
-    return MemoryState::SUSPENDED;
-
-  auto current_state = coordinator_->GetGlobalMemoryState();
-  int expected_renderer_count = available / expected_renderer_size_;
-
-  switch (current_state) {
-    case MemoryState::NORMAL:
-      if (expected_renderer_count <= new_renderers_until_suspended_)
-        return MemoryState::SUSPENDED;
-      if (expected_renderer_count <= new_renderers_until_throttled_)
-        return MemoryState::THROTTLED;
-      return MemoryState::NORMAL;
-    case MemoryState::THROTTLED:
-      if (expected_renderer_count <= new_renderers_until_suspended_)
-        return MemoryState::SUSPENDED;
-      if (expected_renderer_count >= new_renderers_back_to_normal_)
-        return MemoryState::NORMAL;
-      return MemoryState::THROTTLED;
-    case MemoryState::SUSPENDED:
-      if (expected_renderer_count >= new_renderers_back_to_normal_)
-        return MemoryState::NORMAL;
-      if (expected_renderer_count >= new_renderers_back_to_throttled_)
-        return MemoryState::THROTTLED;
-      return MemoryState::SUSPENDED;
-    case MemoryState::UNKNOWN:
-      // Fall through
-    default:
-      NOTREACHED();
-      return MemoryState::UNKNOWN;
-  }
-}
-
-void MemoryStateUpdater::UpdateState() {
-  auto current_state = coordinator_->GetGlobalMemoryState();
-  auto next_state = CalculateNextState();
-  if (coordinator_->ChangeStateIfNeeded(current_state, next_state)) {
-    ScheduleUpdateState(minimum_transition_period_);
-  } else {
-    ScheduleUpdateState(monitoring_interval_);
-  }
-}
-
-void MemoryStateUpdater::ScheduleUpdateState(base::TimeDelta delta) {
-  update_state_closure_.Reset(base::Bind(&MemoryStateUpdater::UpdateState,
-                                         base::Unretained(this)));
-  task_runner_->PostDelayedTask(FROM_HERE, update_state_closure_.callback(),
-                                delta);
-}
-
-void MemoryStateUpdater::InitializeParameters() {
-  expected_renderer_size_ = kDefaultExpectedRendererSizeMB;
-  new_renderers_until_throttled_ = kDefaultNewRenderersUntilThrottled;
-  new_renderers_until_suspended_ = kDefaultNewRenderersUntilSuspended;
-  new_renderers_back_to_normal_ = kDefaultNewRenderersBackToNormal;
-  new_renderers_back_to_throttled_ = kDefaultNewRenderersBackToThrottled;
-  minimum_transition_period_ =
-      base::TimeDelta::FromSeconds(kDefaultMinimumTransitionPeriodSeconds);
-  monitoring_interval_ =
-      base::TimeDelta::FromSeconds(kDefaultMonitoringIntervalSeconds);
-
-  // Override default parameters with variations.
-  static constexpr char kMemoryCoordinatorV0Trial[] = "MemoryCoordinatorV0";
-  std::map<std::string, std::string> params;
-  variations::GetVariationParams(kMemoryCoordinatorV0Trial, &params);
-  // TODO(bashi): Renaming (throttled -> warning, suspended -> critical) is
-  // ongoing. Get variation parameters from both until server-side change
-  // is done. crbug.com/696844
-  SetIntVariationParameter(params, "expected_renderer_size",
-                           &expected_renderer_size_);
-  SetIntVariationParameter(params, "new_renderers_until_throttled",
-                           &new_renderers_until_throttled_);
-  SetIntVariationParameter(params, "new_renderers_until_warning",
-                           &new_renderers_until_throttled_);
-  SetIntVariationParameter(params, "new_renderers_until_suspended",
-                           &new_renderers_until_suspended_);
-  SetIntVariationParameter(params, "new_renderers_until_critical",
-                           &new_renderers_until_suspended_);
-  SetIntVariationParameter(params, "new_renderers_back_to_normal",
-                           &new_renderers_back_to_normal_);
-  SetIntVariationParameter(params, "new_renderers_back_to_throttled",
-                           &new_renderers_back_to_throttled_);
-  SetIntVariationParameter(params, "new_renderers_back_to_warning",
-                           &new_renderers_back_to_throttled_);
-  SetSecondsVariationParameter(params, "minimum_transition_period",
-                               &minimum_transition_period_);
-  SetSecondsVariationParameter(params, "monitoring_interval",
-                               &monitoring_interval_);
-}
-
-bool MemoryStateUpdater::ValidateParameters() {
-  return (new_renderers_until_throttled_ > new_renderers_until_suspended_) &&
-      (new_renderers_back_to_normal_ > new_renderers_back_to_throttled_) &&
-      (new_renderers_back_to_normal_ > new_renderers_until_throttled_) &&
-      (new_renderers_back_to_throttled_ > new_renderers_until_suspended_);
-}
-
-}  // namespace content