Update to current webrtc library

This is from the upstream library commit id
3326535126e435f1ba647885ce43a8f0f3d317eb, corresponding to Chromium
88.0.4290.1.

webrtc/api/scoped_refptr.h

@@ -0,0 +1,164 @@
+/*
+ *  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.
+ */
+
+// Originally these classes are from Chromium.
+// http://src.chromium.org/viewvc/chrome/trunk/src/base/memory/ref_counted.h?view=markup
+
+//
+// A smart pointer class for reference counted objects.  Use this class instead
+// of calling AddRef and Release manually on a reference counted object to
+// avoid common memory leaks caused by forgetting to Release an object
+// reference.  Sample usage:
+//
+//   class MyFoo : public RefCounted<MyFoo> {
+//    ...
+//   };
+//
+//   void some_function() {
+//     scoped_refptr<MyFoo> foo = new MyFoo();
+//     foo->Method(param);
+//     // |foo| is released when this function returns
+//   }
+//
+//   void some_other_function() {
+//     scoped_refptr<MyFoo> foo = new MyFoo();
+//     ...
+//     foo = nullptr;  // explicitly releases |foo|
+//     ...
+//     if (foo)
+//       foo->Method(param);
+//   }
+//
+// The above examples show how scoped_refptr<T> acts like a pointer to T.
+// Given two scoped_refptr<T> classes, it is also possible to exchange
+// references between the two objects, like so:
+//
+//   {
+//     scoped_refptr<MyFoo> a = new MyFoo();
+//     scoped_refptr<MyFoo> b;
+//
+//     b.swap(a);
+//     // now, |b| references the MyFoo object, and |a| references null.
+//   }
+//
+// To make both |a| and |b| in the above example reference the same MyFoo
+// object, simply use the assignment operator:
+//
+//   {
+//     scoped_refptr<MyFoo> a = new MyFoo();
+//     scoped_refptr<MyFoo> b;
+//
+//     b = a;
+//     // now, |a| and |b| each own a reference to the same MyFoo object.
+//   }
+//
+
+#ifndef API_SCOPED_REFPTR_H_
+#define API_SCOPED_REFPTR_H_
+
+#include <memory>
+#include <utility>
+
+namespace rtc {
+
+template <class T>
+class scoped_refptr {
+ public:
+  typedef T element_type;
+
+  scoped_refptr() : ptr_(nullptr) {}
+
+  scoped_refptr(T* p) : ptr_(p) {  // NOLINT(runtime/explicit)
+    if (ptr_)
+      ptr_->AddRef();
+  }
+
+  scoped_refptr(const scoped_refptr<T>& r) : ptr_(r.ptr_) {
+    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) noexcept : ptr_(r.release()) {}
+
+  template <typename U>
+  scoped_refptr(scoped_refptr<U>&& r) noexcept : ptr_(r.release()) {}
+
+  ~scoped_refptr() {
+    if (ptr_)
+      ptr_->Release();
+  }
+
+  T* get() const { return ptr_; }
+  operator T*() const { return ptr_; }
+  T* operator->() const { return ptr_; }
+
+  // Returns the (possibly null) raw pointer, and makes the scoped_refptr hold a
+  // null pointer, all without touching the reference count of the underlying
+  // pointed-to object. The object is still reference counted, and the caller of
+  // release() is now the proud owner of one reference, so it is responsible for
+  // calling Release() once on the object when no longer using it.
+  T* release() {
+    T* retVal = ptr_;
+    ptr_ = nullptr;
+    return retVal;
+  }
+
+  scoped_refptr<T>& operator=(T* p) {
+    // AddRef first so that self assignment should work
+    if (p)
+      p->AddRef();
+    if (ptr_)
+      ptr_->Release();
+    ptr_ = p;
+    return *this;
+  }
+
+  scoped_refptr<T>& operator=(const scoped_refptr<T>& r) {
+    return *this = r.ptr_;
+  }
+
+  template <typename U>
+  scoped_refptr<T>& operator=(const scoped_refptr<U>& r) {
+    return *this = r.get();
+  }
+
+  scoped_refptr<T>& operator=(scoped_refptr<T>&& r) noexcept {
+    scoped_refptr<T>(std::move(r)).swap(*this);
+    return *this;
+  }
+
+  template <typename U>
+  scoped_refptr<T>& operator=(scoped_refptr<U>&& r) noexcept {
+    scoped_refptr<T>(std::move(r)).swap(*this);
+    return *this;
+  }
+
+  void swap(T** pp) noexcept {
+    T* p = ptr_;
+    ptr_ = *pp;
+    *pp = p;
+  }
+
+  void swap(scoped_refptr<T>& r) noexcept { swap(&r.ptr_); }
+
+ protected:
+  T* ptr_;
+};
+
+}  // namespace rtc
+
+#endif  // API_SCOPED_REFPTR_H_