Pass audio to AudioEncoder::Encode() in an ArrayView

webrtc/base/array_view.h

 /*
  *  Copyright 2015 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 43 matching lines @@
   // <vector>); it is handled by the general case in C++11, since std::vector
   // has a data() method there.
   template <typename U>
   ArrayView(std::vector<U>& u)
       : ArrayView(u.empty() ? nullptr : &u[0], u.size()) {}
 
   // Indexing, size, and iteration. These allow mutation even if the ArrayView
   // is const, because the ArrayView doesn't own the array. (To prevent
   // mutation, use ArrayView<const T>.)
   size_t size() const { return size_; }
+  bool empty() const { return size_ == 0; }
   T* data() const { return data_; }
   T& operator[](size_t idx) const {
     RTC_DCHECK_LT(idx, size_);
     RTC_DCHECK(data_);  // Follows from size_ > idx and the class invariant.
     return data_[idx];
   }
   T* begin() const { return data_; }
   T* end() const { return data_ + size_; }
   const T* cbegin() const { return data_; }
   const T* cend() const { return data_ + size_; }
 
+  // Comparing two ArrayViews compares their (pointer,size) pairs; it does
+  // *not* dereference the pointers.
+  friend bool operator==(const ArrayView& a, const ArrayView& b) {
+    return a.data_ == b.data_ && a.size_ == b.size_;
+  }
+  friend bool operator!=(const ArrayView& a, const ArrayView& b) {
+    return !(a == b);
+  }
+
  private:
   // Invariant: !data_ iff size_ == 0.
   void CheckInvariant() const { RTC_DCHECK_EQ(!data_, size_ == 0); }
   T* data_;
   size_t size_;
 };
 
 }  // namespace rtc
 
 #endif  // WEBRTC_BASE_ARRAY_VIEW_H_