Don't call the Pass methods of rtc::Buffer, rtc::scoped_ptr, and rtc::ScopedVector

We can now use std::move instead!

This CL leaves the Pass methods in place; a follow-up CL will add deprecation annotations to them.

Review URL: https://codereview.webrtc.org/1460043002

Cr-Commit-Position: refs/heads/master@{#11064}
diff --git a/webrtc/base/messagehandler.h b/webrtc/base/messagehandler.h
index df82b4e..b55b229 100644
--- a/webrtc/base/messagehandler.h
+++ b/webrtc/base/messagehandler.h
@@ -11,6 +11,8 @@
 #ifndef WEBRTC_BASE_MESSAGEHANDLER_H_
 #define WEBRTC_BASE_MESSAGEHANDLER_H_
 
+#include <utility>
+
 #include "webrtc/base/constructormagic.h"
 #include "webrtc/base/scoped_ptr.h"
 
@@ -54,8 +56,8 @@
     : public MessageHandler {
  public:
   explicit FunctorMessageHandler(const FunctorT& functor) : functor_(functor) {}
-  virtual void OnMessage(Message* msg) { result_ = functor_().Pass(); }
-  rtc::scoped_ptr<ReturnT> result() { return result_.Pass(); }
+  virtual void OnMessage(Message* msg) { result_ = std::move(functor_()); }
+  rtc::scoped_ptr<ReturnT> result() { return std::move(result_); }
 
  private:
   FunctorT functor_;