LibCore+LibIPC: Make Core::Stream read_without_waiting() return Bytes

For the reasoning, see the earlier commit about Core::Stream::read().

Userland/Libraries/LibCore/Stream.cpp

@@ -552,9 +552,9 @@ ErrorOr<pid_t> LocalSocket::peer_pid() const
 #endif
 }
 
-ErrorOr<size_t> LocalSocket::read_without_waiting(Bytes buffer)
+ErrorOr<Bytes> LocalSocket::read_without_waiting(Bytes buffer)
 {
-    return TRY(m_helper.read(buffer, MSG_DONTWAIT)).size();
+    return m_helper.read(buffer, MSG_DONTWAIT);
 }
 
 ErrorOr<int> LocalSocket::release_fd()

Userland/Libraries/LibCore/Stream.h

@@ -444,7 +444,7 @@ public:
     ErrorOr<int> receive_fd(int flags);
     ErrorOr<void> send_fd(int fd);
     ErrorOr<pid_t> peer_pid() const;
-    ErrorOr<size_t> read_without_waiting(Bytes buffer);
+    ErrorOr<Bytes> read_without_waiting(Bytes buffer);
 
     /// Release the fd associated with this LocalSocket. After the fd is
     /// released, the socket will be considered "closed" and all operations done

Userland/Libraries/LibIPC/Connection.cpp

@@ -121,9 +121,9 @@ ErrorOr<Vector<u8>> ConnectionBase::read_as_much_as_possible_from_socket_without
 
     u8 buffer[4096];
     while (m_socket->is_open()) {
-        auto maybe_nread = m_socket->read_without_waiting({ buffer, 4096 });
-        if (maybe_nread.is_error()) {
-            auto error = maybe_nread.release_error();
+        auto maybe_bytes_read = m_socket->read_without_waiting({ buffer, 4096 });
+        if (maybe_bytes_read.is_error()) {
+            auto error = maybe_bytes_read.release_error();
             if (error.is_syscall() && error.code() == EAGAIN) {
                 break;
             }
@@ -133,13 +133,13 @@ ErrorOr<Vector<u8>> ConnectionBase::read_as_much_as_possible_from_socket_without
             VERIFY_NOT_REACHED();
         }
 
-        auto nread = maybe_nread.release_value();
-        if (nread == 0) {
+        auto bytes_read = maybe_bytes_read.release_value();
+        if (bytes_read.is_empty()) {
             deferred_invoke([this] { shutdown(); });
             return Error::from_string_literal("IPC connection EOF"sv);
         }
 
-        bytes.append(buffer, nread);
+        bytes.append(bytes_read.data(), bytes_read.size());
     }
 
     if (!bytes.is_empty()) {