Use TaskScheduler instead of WorkerPool in v8_platform.cc.

content/public/test/render_view_test.h

Index: content/public/test/render_view_test.h
diff --git a/content/public/test/render_view_test.h b/content/public/test/render_view_test.h
index a14e4ec1ef441d92b1fc0bc802620a5c64d28f0d..38d6f4825d371129979ed0406231d23fbf7c0726 100644
--- a/content/public/test/render_view_test.h
+++ b/content/public/test/render_view_test.h
@@ -13,6 +13,7 @@
 #include "base/command_line.h"
 #include "base/message_loop/message_loop.h"
 #include "base/strings/string16.h"
+#include "base/test/scoped_async_task_scheduler.h"
 #include "base/test/test_io_thread.h"
 #include "build/build_config.h"
 #include "content/public/browser/native_web_keyboard_event.h"
@@ -190,7 +191,14 @@ class RenderViewTest : public testing::Test, blink::WebLeakDetectorClient {
   // blink::WebLeakDetectorClient implementation.
   void onLeakDetectionComplete(const Result& result) override;
 
+ private:
   base::MessageLoop msg_loop_;
+
+  // 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_;
+
+ protected:
   std::unique_ptr<FakeCompositorDependencies> compositor_deps_;
   std::unique_ptr<MockRenderProcess> mock_process_;
   // We use a naked pointer because we don't want to expose RenderViewImpl in