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}

webrtc/base/buffer.cc

@@ -11,6 +11,7 @@
 #include "webrtc/base/buffer.h"
 
 #include <cassert>
+#include <utility>
 
 namespace rtc {
 
@@ -22,7 +23,9 @@ Buffer::Buffer(const Buffer& buf) : Buffer(buf.data(), buf.size()) {
 }
 
 Buffer::Buffer(Buffer&& buf)
-    : size_(buf.size()), capacity_(buf.capacity()), data_(buf.data_.Pass()) {
+    : size_(buf.size()),
+      capacity_(buf.capacity()),
+      data_(std::move(buf.data_)) {
   assert(IsConsistent());
   buf.OnMovedFrom();
 }