We no longer use compilers that can't =default move construction and assignment

webrtc/base/optional.h

Index: webrtc/base/optional.h
diff --git a/webrtc/base/optional.h b/webrtc/base/optional.h
index b8071e635876b1b42b4bb7d6b6c10b417d25ad7e..f25086569cbad3cb413488c7bdced19e6cf12816 100644
--- a/webrtc/base/optional.h
+++ b/webrtc/base/optional.h
@@ -69,19 +69,12 @@ class Optional final {
   explicit Optional(T&& val) : value_(std::move(val)), has_value_(true) {}
 
   // Copy and move constructors.
-  // TODO(kwiberg): =default the move constructor when MSVC supports it.
   Optional(const Optional&) = default;
-  Optional(Optional&& m)
-      : value_(std::move(m.value_)), has_value_(m.has_value_) {}
+  Optional(Optional&&) = default;
 
   // Assignment.
-  // TODO(kwiberg): =default the move assignment op when MSVC supports it.
   Optional& operator=(const Optional&) = default;
-  Optional& operator=(Optional&& m) {
-    value_ = std::move(m.value_);
-    has_value_ = m.has_value_;
-    return *this;
-  }
+  Optional& operator=(Optional&&) = default;
 
   friend void swap(Optional& m1, Optional& m2) {
     using std::swap;