Add Callback::IsCancelled

base/callback_internal.cc

Index: base/callback_internal.cc
diff --git a/base/callback_internal.cc b/base/callback_internal.cc
index 303de4d71b84d148557f17bbf388cb35849e0622..e29dd694efb5e2fabc899ef1183fbac333b042b2 100644
--- a/base/callback_internal.cc
+++ b/base/callback_internal.cc
@@ -10,9 +10,12 @@ namespace base {
 namespace internal {
 
 BindStateBase::BindStateBase(InvokeFuncStorage polymorphic_invoke,
-                             void (*destructor)(BindStateBase*))
+                             void (*destructor)(BindStateBase*),
+                             bool (*is_cancelled)(const BindStateBase*))
       : polymorphic_invoke_(polymorphic_invoke),
-        ref_count_(0), destructor_(destructor) {}
+        ref_count_(0),
+        destructor_(destructor),
+        is_cancelled_(is_cancelled) {}
 
 void BindStateBase::AddRef() {
   AtomicRefCountInc(&ref_count_);
@@ -34,6 +37,11 @@ void CallbackBase<CopyMode::MoveOnly>::Reset() {
   bind_state_ = nullptr;
 }
 
+bool CallbackBase<CopyMode::MoveOnly>::IsCancelled() const {
+  DCHECK(bind_state_);
+  return bind_state_->IsCancelled();
+}
+
 bool CallbackBase<CopyMode::MoveOnly>::EqualsInternal(
     const CallbackBase& other) const {
   return bind_state_ == other.bind_state_;