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

webrtc/base/array_view.h

Index: webrtc/base/array_view.h
diff --git a/webrtc/base/array_view.h b/webrtc/base/array_view.h
index 019bd8b6c6b8f37f348f3d8a4d87f742f9602eba..85c814de2a6729190d55249d2b83cc2ae6805984 100644
--- a/webrtc/base/array_view.h
+++ b/webrtc/base/array_view.h
@@ -72,6 +72,18 @@ class ArrayView final {
   const T* cbegin() const { return data_; }
   const T* cend() const { return data_ + size_; }
 
+  // An ArrayView is false iff it's empty.
+  explicit operator bool() const { return size_ > 0; }
+
+  // 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); }