Relanding: Use std::unique_ptr instead of rtc::scoped_refptr in AsyncInvoker.

webrtc/base/messagequeue.h

Index: webrtc/base/messagequeue.h
diff --git a/webrtc/base/messagequeue.h b/webrtc/base/messagequeue.h
index 429a56a8c1e3cd69f6dcafa1b19fbc90dfa51f03..df50f54868a214913761493f15a69c504fc02ee8 100644
--- a/webrtc/base/messagequeue.h
+++ b/webrtc/base/messagequeue.h
@@ -17,6 +17,7 @@
 #include <list>
 #include <memory>
 #include <queue>
+#include <utility>
 #include <vector>
 
 #include "webrtc/base/basictypes.h"
@@ -98,10 +99,21 @@ class TypedMessageData : public MessageData {
 template <class T>
 class ScopedMessageData : public MessageData {
  public:
-  explicit ScopedMessageData(T* data) : data_(data) { }
+  explicit ScopedMessageData(std::unique_ptr<T> data)
+      : data_(std::move(data)) {}
+  // Deprecated.
+  // TODO(deadbeef): Remove this once downstream applications stop using it.
+  explicit ScopedMessageData(T* data) : data_(data) {}
+  // Deprecated.
+  // TODO(deadbeef): Returning a reference to a unique ptr? Why. Get rid of
+  // this once downstream applications stop using it, then rename inner_data to
+  // just data.
   const std::unique_ptr<T>& data() const { return data_; }
   std::unique_ptr<T>& data() { return data_; }
 
+  const T& inner_data() const { return *data_; }
+  T& inner_data() { return *data_; }
+
  private:
   std::unique_ptr<T> data_;
 };