Revert of Use TaskScheduler instead of WorkerPool in v8_platform.cc.

content/renderer/pepper/host_var_tracker_unittest.cc

 // Copyright (c) 2012 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 "content/renderer/pepper/host_var_tracker.h"
 
 #include <memory>
 
 #include "base/macros.h"
-#include "base/test/scoped_async_task_scheduler.h"
 #include "content/renderer/pepper/host_globals.h"
 #include "content/renderer/pepper/mock_resource.h"
 #include "content/renderer/pepper/pepper_plugin_instance_impl.h"
 #include "content/renderer/pepper/pepper_try_catch.h"
 #include "content/renderer/pepper/v8_var_converter.h"
 #include "content/renderer/pepper/v8object_var.h"
 #include "content/test/ppapi_unittest.h"
 #include "gin/handle.h"
 #include "gin/wrappable.h"
 #include "ppapi/c/pp_var.h"
@@ skipping 52 matching lines @@
   HostVarTrackerTest() {}
 
   void TearDown() override {
     v8::Isolate::GetCurrent()->RequestGarbageCollectionForTesting(
         v8::Isolate::kFullGarbageCollection);
     EXPECT_EQ(0, g_v8objects_alive);
     PpapiUnittest::TearDown();
   }
 
   HostVarTracker& tracker() { return *HostGlobals::Get()->host_var_tracker(); }
-
- private:
-  // Required by gin::V8Platform::CallOnBackgroundThread(). Can't be a
-  // ScopedTaskScheduler because v8 synchronously waits for tasks to run.
-  base::test::ScopedAsyncTaskScheduler scoped_async_task_scheduler_;
 };
 
 TEST_F(HostVarTrackerTest, DeleteObjectVarWithInstance) {
   v8::Isolate* test_isolate = v8::Isolate::GetCurrent();
 
   // Make a second instance (the test harness already creates & manages one).
   scoped_refptr<PepperPluginInstanceImpl> instance2(
       PepperPluginInstanceImpl::Create(NULL, module(), NULL, GURL()));
   PP_Instance pp_instance2 = instance2->pp_instance();
 
@@ skipping 41 matching lines @@
   pp_object1 = ppapi::ScopedPPVar();
   pp_object2 = ppapi::ScopedPPVar();
 
   // Releasing the resource should free the internal ref, and so making a new
   // one now should generate a new ID.
   ppapi::ScopedPPVar pp_object3 = try_catch.FromV8(v8_object);
   EXPECT_NE(pp_object1.get().value.as_id, pp_object3.get().value.as_id);
 }
 
 }  // namespace content