[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 fc297cd67b5f47a47cfc3d8475684a30cdfa08a2..4c737cf02f74d315f4f4ff66f61b51385b5167d3 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
@@ -12,6 +12,7 @@
 #include "platform/scheduler/renderer/renderer_scheduler_impl.h"
 #include "platform/scheduler/renderer/web_frame_scheduler_impl.h"
 #include "public/platform/WebFrameScheduler.h"
+#include "web/WebSettingsImpl.h"
 
 namespace blink {
 namespace scheduler {
@@ -20,10 +21,42 @@ namespace {
 
 const double kBackgroundBudgetAsCPUFraction = .01;
 
+double GetBackgroundBudget(WebSettingsImpl* web_settings) {
+  if (!web_settings)
+    return kBackgroundBudgetAsCPUFraction;
+  double web_settings_budget =
+      web_settings->expensiveBackgroundThrottlingCPUBudget();
+  if (web_settings_budget < 0)

[alex clarke (OOO till 29th), 2016/11/02 17:53:48]

< 0.0? (here and below)

[altimin, 2016/11/02 21:10:02]

Done.

+    return kBackgroundBudgetAsCPUFraction;
+  return web_settings_budget;
+}
+
+base::Optional<base::TimeDelta> GetMaxBudgetLevel(
+    WebSettingsImpl* web_settings) {
+  if (!web_settings)
+    return base::nullopt;
+  double max_budget_level =
+      web_settings->expensiveBackgroundThrottlingMaxBudget();
+  if (max_budget_level < 0)
+    return base::nullopt;
+  return base::TimeDelta::FromSecondsD(max_budget_level);
+}
+
+base::Optional<base::TimeDelta> GetMaxThrottlingDelay(
+    WebSettingsImpl* web_settings) {
+  if (!web_settings)
+    return base::nullopt;
+  double max_delay = web_settings->expensiveBackgroundThrottlingMaxDelay();
+  if (max_delay < 0)
+    return base::nullopt;
+  return base::TimeDelta::FromSecondsD(max_delay);
+}
+
 }  // namespace
 
 WebViewSchedulerImpl::WebViewSchedulerImpl(
     WebScheduler::InterventionReporter* intervention_reporter,
+    WebSettingsImpl* web_settings,
     RendererSchedulerImpl* renderer_scheduler,
     bool disable_background_timer_throttling)
     : intervention_reporter_(intervention_reporter),
@@ -36,22 +69,9 @@ WebViewSchedulerImpl::WebViewSchedulerImpl(
       have_seen_loading_task_(false),
       virtual_time_(false),
       is_audio_playing_(false),
-      background_time_budget_pool_(nullptr) {
+      background_time_budget_pool_(nullptr),
+      web_settings_(web_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() {
@@ -189,5 +209,34 @@ void WebViewSchedulerImpl::ApplyVirtualTimePolicy() {
                                have_seen_loading_task_);
 }
 
+TaskQueueThrottler::TimeBudgetPool*
+WebViewSchedulerImpl::BackgroundTimeBudgetPool() {
+  if (!background_time_budget_pool_)
+    MaybeInitializeBackgroundTimeBudgetPool();
+  return background_time_budget_pool_;
+}
+
+void WebViewSchedulerImpl::MaybeInitializeBackgroundTimeBudgetPool() {
+  if (!RuntimeEnabledFeatures::expensiveBackgroundTimerThrottlingEnabled())
+    return;
+
+  background_time_budget_pool_ =

[alex clarke (OOO till 29th), 2016/11/02 17:53:49]

DCHECK background_time_budget_pool_ isn't already initialized?

[altimin, 2016/11/02 21:10:01]

Replaced with checking and exiting the function.

+      renderer_scheduler_->task_queue_throttler()->CreateTimeBudgetPool(
+          "background", GetMaxBudgetLevel(web_settings_),
+          GetMaxThrottlingDelay(web_settings_));
+
+  LazyNow lazy_now(renderer_scheduler_->tick_clock());
+
+  // Disable throttling because page is visible by default.
+  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(web_settings_));
+}
+
 }  // namespace scheduler
 }  // namespace blink