Revert "[scheduler] Throttle background frames with 1% CPU limit"

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 25a8d673c971db4e049ba2043581f6012b40a1e8..0dff1a2d6b38baccd3a8f9aa57ad7765673fa251 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
@@ -5,7 +5,6 @@
 #include "platform/scheduler/renderer/web_view_scheduler_impl.h"
 
 #include "base/logging.h"
-#include "platform/RuntimeEnabledFeatures.h"
 #include "platform/scheduler/base/virtual_time_domain.h"
 #include "platform/scheduler/child/scheduler_tqm_delegate.h"
 #include "platform/scheduler/renderer/auto_advancing_virtual_time_domain.h"
@@ -16,12 +15,6 @@
 namespace blink {
 namespace scheduler {
 
-namespace {
-
-const double kBackgroundBudgetAsCPUFraction = .01;
-
-}  // namespace
-
 WebViewSchedulerImpl::WebViewSchedulerImpl(
     WebScheduler::InterventionReporter* intervention_reporter,
     RendererSchedulerImpl* renderer_scheduler,
@@ -34,23 +27,8 @@ WebViewSchedulerImpl::WebViewSchedulerImpl(
       disable_background_timer_throttling_(disable_background_timer_throttling),
       allow_virtual_time_to_advance_(true),
       have_seen_loading_task_(false),
-      virtual_time_(false),
-      background_time_budget_pool_(nullptr) {
+      virtual_time_(false) {
   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() {
@@ -60,9 +38,6 @@ WebViewSchedulerImpl::~WebViewSchedulerImpl() {
     frame_scheduler->DetachFromWebViewScheduler();
   }
   renderer_scheduler_->RemoveWebViewScheduler(this);
-
-  if (background_time_budget_pool_)
-    background_time_budget_pool_->Close();
 }
 
 void WebViewSchedulerImpl::setPageVisible(bool page_visible) {
@@ -74,15 +49,6 @@ void WebViewSchedulerImpl::setPageVisible(bool page_visible) {
   for (WebFrameSchedulerImpl* frame_scheduler : frame_schedulers_) {
     frame_scheduler->setPageVisible(page_visible_);
   }
-
-  if (background_time_budget_pool_) {
-    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);
-    }
-  }
 }
 
 std::unique_ptr<WebFrameSchedulerImpl>