Revert "[gin] Allow posting non-nestable tasks through V8"

This reverts commit 7f08809a.

Reason for revert: broke compilation
https://logs.chromium.org/logs/chromium/buildbucket/cr-buildbucket.appspot.com/8932945363042209344/+/steps/compile/0/stdout

../../gin/v8_foreground_task_runner.h:27:60: error: only virtual member functions can be marked 'override'
    void PostNonNestableTask(std::unique_ptr<v8::Task> task) override;
                                                             ^~~~~~~~
  ../../gin/v8_foreground_task_runner.h:34:40: error: only virtual member functions can be marked 'override'
    bool NonNestableTasksEnabled() const override;

Original change's description:
> [gin] Allow posting non-nestable tasks through V8
> 
> Will be used to allow V8 posting top-level tasks.
> 
> Bug: chromium:843903
> Change-Id: I97caa705b561fa8832ef8a11abfc3eefe47ec3f8
> Reviewed-on: https://chromium-review.googlesource.com/c/1273140
> Reviewed-by: Jochen Eisinger <jochen@chromium.org>
> Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#598802}

TBR=mlippautz@chromium.org,jochen@chromium.org

Change-Id: I5d427abfe85e3b69a3d649ee190406a5d9583d9e
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: chromium:843903
Reviewed-on: https://chromium-review.googlesource.com/c/1277086Reviewed-by: Vasilii Sukhanov <vasilii@chromium.org>
Commit-Queue: Vasilii Sukhanov <vasilii@chromium.org>
Cr-Commit-Position: refs/heads/master@{#598804}

gin/v8_foreground_task_runner.cc

@@ -24,12 +24,6 @@ void V8ForegroundTaskRunner::PostTask(std::unique_ptr<v8::Task> task) {
                          base::BindOnce(&v8::Task::Run, std::move(task)));
 }
 
-void V8ForegroundTaskRunner::PostNonNestableTask(
-    std::unique_ptr<v8::Task> task) {
-  task_runner_->PostNonNestableTask(
-      FROM_HERE, base::BindOnce(&v8::Task::Run, std::move(task)));
-}
-
 void V8ForegroundTaskRunner::PostDelayedTask(std::unique_ptr<v8::Task> task,
                                              double delay_in_seconds) {
   task_runner_->PostDelayedTask(
@@ -42,8 +36,4 @@ void V8ForegroundTaskRunner::PostIdleTask(std::unique_ptr<v8::IdleTask> task) {
   idle_task_runner()->PostIdleTask(std::move(task));
 }
 
-bool V8ForegroundTaskRunner::NonNestableTasksEnabled() const {
-  return true;
-}
-
 }  // namespace gin

gin/v8_foreground_task_runner.h

@@ -24,15 +24,11 @@ class V8ForegroundTaskRunner : public V8ForegroundTaskRunnerBase {
   // v8::Platform implementation.
   void PostTask(std::unique_ptr<v8::Task> task) override;
 
-  void PostNonNestableTask(std::unique_ptr<v8::Task> task) override;
-
   void PostDelayedTask(std::unique_ptr<v8::Task> task,
                        double delay_in_seconds) override;
 
   void PostIdleTask(std::unique_ptr<v8::IdleTask> task) override;
 
-  bool NonNestableTasksEnabled() const override;
-
  private:
   scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
 };

gin/v8_foreground_task_runner_with_locker.cc

@@ -57,13 +57,6 @@ void V8ForegroundTaskRunnerWithLocker::PostTask(
                                 std::move(task)));
 }
 
-void V8ForegroundTaskRunnerWithLocker::PostNonNestableTask(
-    std::unique_ptr<v8::Task> task) {
-  task_runner_->PostNonNestableTask(
-      FROM_HERE, base::BindOnce(RunWithLocker, base::Unretained(isolate_),
-                                std::move(task)));
-}
-
 void V8ForegroundTaskRunnerWithLocker::PostDelayedTask(
     std::unique_ptr<v8::Task> task,
     double delay_in_seconds) {
@@ -81,8 +74,4 @@ void V8ForegroundTaskRunnerWithLocker::PostIdleTask(
       std::make_unique<IdleTaskWithLocker>(isolate_, std::move(task)));
 }
 
-bool V8ForegroundTaskRunnerWithLocker::NonNestableTasksEnabled() const {
-  return true;
-}
-
 }  // namespace gin

gin/v8_foreground_task_runner_with_locker.h

@@ -25,15 +25,11 @@ class V8ForegroundTaskRunnerWithLocker : public V8ForegroundTaskRunnerBase {
   // v8::Platform implementation.
   void PostTask(std::unique_ptr<v8::Task> task) override;
 
-  void PostNonNestableTask(std::unique_ptr<v8::Task> task) override;
-
   void PostDelayedTask(std::unique_ptr<v8::Task> task,
                        double delay_in_seconds) override;
 
   void PostIdleTask(std::unique_ptr<v8::IdleTask> task) override;
 
-  bool NonNestableTasksEnabled() const override;
-
  private:
   v8::Isolate* isolate_;
   scoped_refptr<base::SingleThreadTaskRunner> task_runner_;