Allow expensive task blocking if there is pending iframe navigation

components/scheduler/renderer/renderer_scheduler.h

Index: components/scheduler/renderer/renderer_scheduler.h
diff --git a/components/scheduler/renderer/renderer_scheduler.h b/components/scheduler/renderer/renderer_scheduler.h
index 7bf5c7fe9e928370ffe302f3cfc7fcd2e32ca161..1af60858fcd238af926619e9ad4c33bb2b326363 100644
--- a/components/scheduler/renderer/renderer_scheduler.h
+++ b/components/scheduler/renderer/renderer_scheduler.h
@@ -128,14 +128,15 @@ class SCHEDULER_EXPORT RendererScheduler : public ChildScheduler {
   // Must be called on the main thread.
   virtual void OnRendererForegrounded() = 0;
 
-  // Tells the scheduler that a navigation task is pending. While any navigation
-  // tasks are pending, the scheduler will ensure that loading tasks are not
-  // blocked even if they are expensive. Must be called on the main thread.
-  virtual void AddPendingNavigation() = 0;
+  // Tells the scheduler that a navigation task is pending. While any main-frame
+  // navigation tasks are pending, the scheduler will ensure that loading tasks
+  // are not blocked even if they are expensive. Must be called on the main
+  // thread.
+  virtual void AddPendingNavigation(bool main_frame_navigating) = 0;
 
   // Tells the scheduler that a navigation task is no longer pending.
   // Must be called on the main thread.
-  virtual void RemovePendingNavigation() = 0;
+  virtual void RemovePendingNavigation(bool main_frame_navigating) = 0;
 
   // Tells the scheduler that a navigation has started.  The scheduler will
   // prioritize loading tasks for a short duration afterwards.