Use scoped_refptr for On(Add|Remove)Stream and OnDataChannel.

webrtc/base/scoped_ref_ptr.h

 /*
  *  Copyright 2011 The WebRTC Project Authors. All rights reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 71 matching lines @@
     if (ptr_)
       ptr_->AddRef();
   }
 
   template <typename U>
   scoped_refptr(const scoped_refptr<U>& r) : ptr_(r.get()) {
     if (ptr_)
       ptr_->AddRef();
   }
 
+  // Move constructors.
+  scoped_refptr(scoped_refptr<T>&& r) : ptr_(r.release()) {}
+
+  template <typename U>
+  scoped_refptr(scoped_refptr<U>&& r) : ptr_(r.release()) {}
+
   ~scoped_refptr() {
     if (ptr_)
       ptr_->Release();
   }
 
   T* get() const { return ptr_; }
   operator T*() const { return ptr_; }
   T* operator->() const { return ptr_; }
 
   // Release a pointer.
@@ skipping 36 matching lines @@
     swap(&r.ptr_);
   }
 
  protected:
   T* ptr_;
 };
 
 }  // namespace rtc
 
 #endif  // WEBRTC_BASE_SCOPED_REF_PTR_H_