Allow expensive task blocking if there is pending iframe navigation

third_party/WebKit/public/platform/WebScheduler.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef WebScheduler_h
 #define WebScheduler_h
 
 #include "WebCommon.h"
 #include "public/platform/WebTaskRunner.h"
 #include "public/platform/WebThread.h"
@@ skipping 63 matching lines @@
     // Suspends the timer queue and increments the timer queue suspension count.
     // May only be called from the main thread.
     virtual void suspendTimerQueue() = 0;
 
     // Decrements the timer queue suspension count and re-enables the timer queue
     // if the suspension count is zero and the current scheduler policy allows it.
     virtual void resumeTimerQueue() = 0;
 
     // Tells the scheduler that a navigation task is pending.
     // TODO(alexclarke): Long term should this be a task trait?
-    virtual void addPendingNavigation() = 0;
+    virtual void addPendingNavigation(bool mainFrameNavigating) = 0;

[Sami, 2016/05/09 16:45:21]

I'm tempted to suggest making this an enum instead for readability. WDYT?

[alex clarke (OOO till 29th), 2016/05/09 17:08:09]

Yeah I was tempted to do that too, but didn't initially.  It's done now.

 
     // Tells the scheduler that a navigation task is no longer pending.
-    virtual void removePendingNavigation() = 0;
+    virtual void removePendingNavigation(bool mainFrameNavigating) = 0;
 
     // Tells the scheduler that an expected navigation was started.
     virtual void onNavigationStarted() = 0;
 
 #ifdef INSIDE_BLINK
     // Helpers for posting bound functions as tasks.
     typedef Function<void(double deadlineSeconds)> IdleTask;
 
     void postIdleTask(const WebTraceLocation&, PassOwnPtr<IdleTask>);
     void postNonNestableIdleTask(const WebTraceLocation&, PassOwnPtr<IdleTask>);
     void postIdleTaskAfterWakeup(const WebTraceLocation&, PassOwnPtr<IdleTask>);
 #endif
 };
 
 } // namespace blink
 
 #endif // WebScheduler_h