Merge 237541 "Revert of https://codereview.chromium.org/71013004/"

base/win/scoped_handle.h

Index: base/win/scoped_handle.h
===================================================================
--- base/win/scoped_handle.h	(revision 237598)
+++ base/win/scoped_handle.h	(working copy)
@@ -39,6 +39,22 @@
  public:
   typedef typename Traits::Handle Handle;
 
+  // Helper object to contain the effect of Receive() to the function that needs
+  // a pointer, and allow proper tracking of the handle.
+  class Receiver {
+   public:
+    explicit Receiver(GenericScopedHandle* owner)
+        : handle_(Traits::NullHandle()),
+          owner_(owner) {}
+    ~Receiver() { owner_->Set(handle_); }
+
+    operator Handle*() { return &handle_; }
+
+   private:
+    Handle handle_;
+    GenericScopedHandle* owner_;
+  };
+
   GenericScopedHandle() : handle_(Traits::NullHandle()) {}
 
   explicit GenericScopedHandle(Handle handle) : handle_(Traits::NullHandle()) {
@@ -86,6 +102,16 @@
     return handle_;
   }
 
+  // This method is intended to be used with functions that require a pointer to
+  // a destination handle, like so:
+  //    void CreateRequiredHandle(Handle* out_handle);
+  //    ScopedHandle a;
+  //    CreateRequiredHandle(a.Receive());
+  Receiver Receive() {
+    DCHECK(!Traits::IsHandleValid(handle_)) << "Handle must be NULL";
+    return Receiver(this);
+  }
+
   // Transfers ownership away from this object.
   Handle Take() {
     Handle temp = handle_;