rtc::Buffer: Let SetData and AppendData accept anything with .data() and .size()

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 725a2d79d6f6fcc055e787dc7627889b30f74569..59e0395199f152a5e405d3cb1b53bc3edfd7966d 100644
--- a/webrtc/base/array_view.h
+++ b/webrtc/base/array_view.h
@@ -11,37 +11,11 @@
 #ifndef WEBRTC_BASE_ARRAY_VIEW_H_
 #define WEBRTC_BASE_ARRAY_VIEW_H_
 
-#include <type_traits>
-
 #include "webrtc/base/checks.h"
+#include "webrtc/base/type_traits.h"
 
 namespace rtc {
 
-namespace internal {
-
-// (Internal; please don't use outside this file.) Determines if the given
-// class has zero-argument .data() and .size() methods whose return values are
-// convertible to T* and size_t, respectively.
-template <typename DS, typename T>
-class HasDataAndSize {
- private:
-  template <
-      typename C,
-      typename std::enable_if<
-          std::is_convertible<decltype(std::declval<C>().data()), T*>::value &&
-          std::is_convertible<decltype(std::declval<C>().size()),
-                              size_t>::value>::type* = nullptr>
-  static int Test(int);
-
-  template <typename>
-  static char Test(...);
-
- public:
-  static constexpr bool value = std::is_same<decltype(Test<DS>(0)), int>::value;
-};
-
-}  // namespace internal
-
 // Many functions read from or write to arrays. The obvious way to do this is
 // to use two arguments, a pointer to the first element and an element count:
 //
@@ -122,9 +96,9 @@ class ArrayView final {
   // or ArrayView<const T>, const std::vector<T> to ArrayView<const T>, and
   // rtc::Buffer to ArrayView<uint8_t> (with the same const behavior as
   // std::vector).
-  template <typename U,
-            typename std::enable_if<
-                internal::HasDataAndSize<U, T>::value>::type* = nullptr>
+  template <
+      typename U,
+      typename std::enable_if<HasDataAndSize<U, T>::value>::type* = nullptr>
   ArrayView(U& u) : ArrayView(u.data(), u.size()) {}
 
   // Indexing, size, and iteration. These allow mutation even if the ArrayView