[scheduler] Use Finch to control background throttling.

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

Index: third_party/WebKit/Source/platform/scheduler/renderer/web_view_scheduler_impl.h
diff --git a/third_party/WebKit/Source/platform/scheduler/renderer/web_view_scheduler_impl.h b/third_party/WebKit/Source/platform/scheduler/renderer/web_view_scheduler_impl.h
index e724e46f81cead0ee9c476bf77752ea5ca1ed7d0..3969cc567f1d62f8e93649eb386d0764c9d43efb 100644
--- a/third_party/WebKit/Source/platform/scheduler/renderer/web_view_scheduler_impl.h
+++ b/third_party/WebKit/Source/platform/scheduler/renderer/web_view_scheduler_impl.h
@@ -24,6 +24,8 @@ class SingleThreadTaskRunner;
 }  // namespace base
 
 namespace blink {
+class WebSettingsImpl;
+
 namespace scheduler {
 
 class RendererSchedulerImpl;
@@ -33,6 +35,7 @@ class BLINK_PLATFORM_EXPORT WebViewSchedulerImpl : public WebViewScheduler {
  public:
   WebViewSchedulerImpl(
       WebScheduler::InterventionReporter* intervention_reporter,
+      WebSettingsImpl* web_settings,
       RendererSchedulerImpl* renderer_scheduler,
       bool disable_background_timer_throttling);
 
@@ -63,11 +66,9 @@ class BLINK_PLATFORM_EXPORT WebViewSchedulerImpl : public WebViewScheduler {
 
   bool IsAudioPlaying() const;
 
-  TaskQueueThrottler::TimeBudgetPool* background_time_budget_pool() const {
-    return background_time_budget_pool_;
-  }
+  TaskQueueThrottler::TimeBudgetPool* BackgroundTimeBudgetPool();
+  void MaybeInitializeBackgroundTimeBudgetPool();
 
- private:
   void setAllowVirtualTimeToAdvance(bool allow_virtual_time_to_advance);
   void ApplyVirtualTimePolicy();
 
@@ -85,6 +86,8 @@ class BLINK_PLATFORM_EXPORT WebViewSchedulerImpl : public WebViewScheduler {
   bool is_audio_playing_;
   TaskQueueThrottler::TimeBudgetPool*
       background_time_budget_pool_;  // Not owned.
+  // WebSettings is owned by corresponding WebView.
+  const WebSettingsImpl* web_settings_;  // Not owned.
 
   DISALLOW_COPY_AND_ASSIGN(WebViewSchedulerImpl);
 };