Replace Closure in TaskRunner::PostTask with OneShotCallback

base/critical_closure.h

Index: base/critical_closure.h
diff --git a/base/critical_closure.h b/base/critical_closure.h
index 6ebd7afa503ce66d6b12c36fe5bfb9d1dbb80103..9970976ed71f7d5bde46feb6754555fea2c69c24 100644
--- a/base/critical_closure.h
+++ b/base/critical_closure.h
@@ -22,27 +22,13 @@ namespace internal {
 // Returns true if multi-tasking is supported on this iOS device.
 bool IsMultiTaskingSupported();
 
-// This class wraps a closure so it can continue to run for a period of time
+// This function wraps a closure so it can continue to run for a period of time
 // when the application goes to the background by using
 // |ios::ScopedCriticalAction|.
-template <typename R>
-class CriticalClosure {
- public:
-  explicit CriticalClosure(const Callback<R(void)>& closure)
-      : closure_(closure) {}
-
-  ~CriticalClosure() {}
-
-  R Run() {
-    return closure_.Run();
-  }
-
- private:
-  ios::ScopedCriticalAction critical_action_;
-  Callback<R(void)> closure_;
-
-  DISALLOW_COPY_AND_ASSIGN(CriticalClosure);
-};
+template <typename R, typename CallbackType>
+R RunCriticalClosure(ios::ScopedCriticalAction*, CallbackType closure) {
+  return std::forward<CallbackType>(closure).Run();
+}
 #endif  // defined(OS_IOS)
 
 }  // namespace internal
@@ -63,14 +49,28 @@ class CriticalClosure {
 // before posting.
 #if defined(OS_IOS)
 template <typename R>
-Callback<R(void)> MakeCriticalClosure(const Callback<R(void)>& closure) {
+RepeatingCallback<R()> MakeCriticalClosure(RepeatingCallback<R()> closure) {
   DCHECK(internal::IsMultiTaskingSupported());
-  return base::Bind(&internal::CriticalClosure<R>::Run,
-                    Owned(new internal::CriticalClosure<R>(closure)));
+  return base::BindRepeating(
+      &internal::RunCriticalClosure<R, RepeatingCallback<R()>>,
+      base::Owned(new ios::ScopedCriticalAction),
+      std::move(closure));
 }
-#else  // defined(OS_IOS)
+
 template <typename R>
-inline Callback<R(void)> MakeCriticalClosure(const Callback<R(void)>& closure) {
+OnceCallback<R()> MakeCriticalClosure(OnceCallback<R()> closure) {
+  DCHECK(internal::IsMultiTaskingSupported());
+  return base::BindOnce(
+      &internal::RunCriticalClosure<R, OnceCallback<R()>>,
+      base::Owned(new ios::ScopedCriticalAction),
+      std::move(closure));
+}
+#else  // defined(OS_IOS)
+template <typename R,
+          internal::CopyMode copy_mode,
+          internal::RepeatMode repeat_mode>
+inline Callback<R(), copy_mode, repeat_mode> MakeCriticalClosure(
+    Callback<R(), copy_mode, repeat_mode> closure) {
   // No-op for platforms where the application does not need to acquire
   // background time for closures to finish when it goes into the background.
   return closure;