scheduler: Disable expensive task blocking policy in M48

components/scheduler/renderer/renderer_scheduler_impl.cc

 // 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.
 
 #include "components/scheduler/renderer/renderer_scheduler_impl.h"
 
 #include "base/bind.h"
 #include "base/debug/stack_trace.h"
 #include "base/logging.h"
 #include "base/trace_event/trace_event.h"
@@ skipping 697 matching lines @@
     block_expensive_loading_tasks = false;
     block_expensive_timer_tasks = false;
   }
 
   // Don't block expensive tasks if we are expecting a navigation.
   if (MainThreadOnly().navigation_task_expected_count > 0) {
     block_expensive_loading_tasks = false;
     block_expensive_timer_tasks = false;
   }
 
+  // Expensive task blocking is currently disabled (crbug.com/574343).
+  block_expensive_loading_tasks = false;
+  block_expensive_timer_tasks = false;
+
   // Only block expensive tasks if we have seen a touch start, i.e. don't block
   // expensive timers on desktop because it's causing too many problems with
   // legitimate webcontent using mousehandlers for various things.
   // See http://crbug.com/570845 and http://crbug.com/570845 for details.
   // TODO(alexclarke): Revisit the throttling decisions and mechanism.
   if (!AnyThread().have_seen_touchstart) {
     block_expensive_loading_tasks = false;
     block_expensive_timer_tasks = false;
   }
 
@@ skipping 324 matching lines @@
 double RendererSchedulerImpl::CurrentTimeSeconds() const {
   return helper_.scheduler_tqm_delegate()->CurrentTimeSeconds();
 }
 
 double RendererSchedulerImpl::MonotonicallyIncreasingTimeSeconds() const {
   return helper_.scheduler_tqm_delegate()->NowTicks().ToInternalValue() /
          static_cast<double>(base::Time::kMicrosecondsPerSecond);
 }
 
 }  // namespace scheduler