Make nesting/running states a RunLoop rather than a MessageLoop concept.

third_party/WebKit/Source/platform/scheduler/test/lazy_scheduler_message_loop_delegate_for_tests.cc

Index: third_party/WebKit/Source/platform/scheduler/test/lazy_scheduler_message_loop_delegate_for_tests.cc
diff --git a/third_party/WebKit/Source/platform/scheduler/test/lazy_scheduler_message_loop_delegate_for_tests.cc b/third_party/WebKit/Source/platform/scheduler/test/lazy_scheduler_message_loop_delegate_for_tests.cc
index bd41c59fef331ffed136343a1e3a45d4f71680ac..0a0d08baeba30add86aa15923f39df47ad88fc22 100644
--- a/third_party/WebKit/Source/platform/scheduler/test/lazy_scheduler_message_loop_delegate_for_tests.cc
+++ b/third_party/WebKit/Source/platform/scheduler/test/lazy_scheduler_message_loop_delegate_for_tests.cc
@@ -7,6 +7,7 @@
 #include <utility>
 
 #include "base/memory/ptr_util.h"
+#include "base/run_loop.h"
 #include "base/time/default_tick_clock.h"
 
 namespace blink {
@@ -22,8 +23,7 @@ LazySchedulerMessageLoopDelegateForTests::
     LazySchedulerMessageLoopDelegateForTests()
     : message_loop_(base::MessageLoop::current()),
       thread_id_(base::PlatformThread::CurrentId()),
-      time_source_(base::MakeUnique<base::DefaultTickClock>()),
-      pending_observer_(nullptr) {
+      time_source_(base::MakeUnique<base::DefaultTickClock>()) {
   if (message_loop_)
     original_task_runner_ = message_loop_->task_runner();
 }
@@ -43,8 +43,6 @@ base::MessageLoop* LazySchedulerMessageLoopDelegateForTests::EnsureMessageLoop()
   original_task_runner_ = message_loop_->task_runner();
   if (pending_task_runner_)
     message_loop_->SetTaskRunner(std::move(pending_task_runner_));
-  if (pending_observer_)
-    message_loop_->AddNestingObserver(pending_observer_);
   return message_loop_;
 }
 
@@ -90,26 +88,19 @@ bool LazySchedulerMessageLoopDelegateForTests::RunsTasksOnCurrentThread()
 }
 
 bool LazySchedulerMessageLoopDelegateForTests::IsNested() const {
-  return EnsureMessageLoop()->IsNested();
+  DCHECK(RunsTasksOnCurrentThread());
+  EnsureMessageLoop();
+  return base::RunLoop::IsNestedOnCurrentThread();
 }
 
 void LazySchedulerMessageLoopDelegateForTests::AddNestingObserver(
-    base::MessageLoop::NestingObserver* observer) {
-  if (!HasMessageLoop()) {
-    pending_observer_ = observer;
-    return;
-  }
-  message_loop_->AddNestingObserver(observer);
+    base::RunLoop::NestingObserver* observer) {
+  base::RunLoop::AddNestingObserverOnCurrentThread(observer);
 }
 
 void LazySchedulerMessageLoopDelegateForTests::RemoveNestingObserver(
-    base::MessageLoop::NestingObserver* observer) {
-  if (!message_loop_ || message_loop_ != base::MessageLoop::current()) {
-    DCHECK_EQ(pending_observer_, observer);
-    pending_observer_ = nullptr;
-    return;
-  }
-  message_loop_->RemoveNestingObserver(observer);
+    base::RunLoop::NestingObserver* observer) {
+  base::RunLoop::AddNestingObserverOnCurrentThread(observer);
 }
 
 base::TimeTicks LazySchedulerMessageLoopDelegateForTests::NowTicks() {