[scheduler] Use Finch to control background throttling.

third_party/WebKit/Source/platform/scheduler/renderer/web_view_scheduler_impl.cc

Index: third_party/WebKit/Source/platform/scheduler/renderer/web_view_scheduler_impl.cc
diff --git a/third_party/WebKit/Source/platform/scheduler/renderer/web_view_scheduler_impl.cc b/third_party/WebKit/Source/platform/scheduler/renderer/web_view_scheduler_impl.cc
index f7ba68c71c706abc2f5cb8692294400ea498420e..3b4141f36921eef41f07d131133201feb1e918a2 100644
--- a/third_party/WebKit/Source/platform/scheduler/renderer/web_view_scheduler_impl.cc
+++ b/third_party/WebKit/Source/platform/scheduler/renderer/web_view_scheduler_impl.cc
@@ -20,10 +20,40 @@ namespace {
 
 const double kBackgroundBudgetAsCPUFraction = .01;
 
+double GetBackgroundBudget(WebScheduler::WebSchedulerSettings* settings) {
+  if (!settings)
+    return kBackgroundBudgetAsCPUFraction;
+  double settings_budget = settings->expensiveBackgroundThrottlingCPUBudget();
+  if (settings_budget < 0.0)
+    return kBackgroundBudgetAsCPUFraction;
+  return settings_budget;
+}
+
+base::Optional<base::TimeDelta> GetMaxBudgetLevel(
+    WebScheduler::WebSchedulerSettings* settings) {
+  if (!settings)
+    return base::nullopt;
+  double max_budget_level = settings->expensiveBackgroundThrottlingMaxBudget();
+  if (max_budget_level < 0.0)
+    return base::nullopt;
+  return base::TimeDelta::FromSecondsD(max_budget_level);
+}
+
+base::Optional<base::TimeDelta> GetMaxThrottlingDelay(
+    WebScheduler::WebSchedulerSettings* settings) {
+  if (!settings)
+    return base::nullopt;
+  double max_delay = settings->expensiveBackgroundThrottlingMaxDelay();
+  if (max_delay < 0.0)
+    return base::nullopt;
+  return base::TimeDelta::FromSecondsD(max_delay);
+}
+
 }  // namespace
 
 WebViewSchedulerImpl::WebViewSchedulerImpl(
     WebScheduler::InterventionReporter* intervention_reporter,
+    WebScheduler::WebSchedulerSettings* settings,
     RendererSchedulerImpl* renderer_scheduler,
     bool disable_background_timer_throttling)
     : intervention_reporter_(intervention_reporter),
@@ -36,22 +66,9 @@ WebViewSchedulerImpl::WebViewSchedulerImpl(
       have_seen_loading_task_(false),
       virtual_time_(false),
       is_audio_playing_(false),
-      background_time_budget_pool_(nullptr) {
+      background_time_budget_pool_(nullptr),
+      settings_(settings) {
   renderer_scheduler->AddWebViewScheduler(this);
-
-  if (RuntimeEnabledFeatures::expensiveBackgroundTimerThrottlingEnabled()) {
-    background_time_budget_pool_ =
-        renderer_scheduler_->task_queue_throttler()->CreateTimeBudgetPool(
-            "background");
-
-    LazyNow lazy_now(renderer_scheduler_->tick_clock());
-
-    // Disable throttling because page is visible by default.
-    background_time_budget_pool_->DisableThrottling(&lazy_now);
-
-    background_time_budget_pool_->SetTimeBudget(lazy_now.Now(),
-                                                kBackgroundBudgetAsCPUFraction);
-  }
 }
 
 WebViewSchedulerImpl::~WebViewSchedulerImpl() {
@@ -198,5 +215,35 @@ bool WebViewSchedulerImpl::IsAudioPlaying() const {
   return is_audio_playing_;
 }
 
+TaskQueueThrottler::TimeBudgetPool*
+WebViewSchedulerImpl::BackgroundTimeBudgetPool() {
+  MaybeInitializeBackgroundTimeBudgetPool();
+  return background_time_budget_pool_;
+}
+
+void WebViewSchedulerImpl::MaybeInitializeBackgroundTimeBudgetPool() {
+  if (background_time_budget_pool_)
+    return;
+
+  if (!RuntimeEnabledFeatures::expensiveBackgroundTimerThrottlingEnabled())
+    return;
+
+  background_time_budget_pool_ =
+      renderer_scheduler_->task_queue_throttler()->CreateTimeBudgetPool(
+          "background", GetMaxBudgetLevel(settings_),
+          GetMaxThrottlingDelay(settings_));
+
+  LazyNow lazy_now(renderer_scheduler_->tick_clock());
+
+  if (page_visible_) {
+    background_time_budget_pool_->DisableThrottling(&lazy_now);
+  } else {
+    background_time_budget_pool_->EnableThrottling(&lazy_now);
+  }
+
+  background_time_budget_pool_->SetTimeBudget(lazy_now.Now(),
+                                              GetBackgroundBudget(settings_));
+}
+
 }  // namespace scheduler
 }  // namespace blink