LibGUI: Make the Clipboard API deal in raw byte buffers a bit more

To open up for putting not just text/plain content on the clipboard,
let's make the GUI::Clipboard API a bit more raw-data-friendly. :^)

Libraries/LibGUI/Clipboard.cpp

@@ -90,26 +90,26 @@ Clipboard::DataAndType Clipboard::data_and_type() const
         dbgprintf("GUI::Clipboard::data() clipping contents size is greater than shared buffer size\n");
         return {};
     }
-    auto data = String((const char*)shared_buffer->data(), response->data_size());
+    auto data = ByteBuffer::copy(shared_buffer->data(), response->data_size());
     auto type = response->mime_type();
     return { data, type };
 }
 
-void Clipboard::set_data(const StringView& data, const String& type)
+void Clipboard::set_data(ReadonlyBytes data, const String& type)
 {
-    auto shared_buffer = SharedBuffer::create_with_size(data.length() + 1);
+    auto shared_buffer = SharedBuffer::create_with_size(data.size() + 1);
     if (!shared_buffer) {
         dbgprintf("GUI::Clipboard::set_data() failed to create a shared buffer\n");
         return;
     }
     if (!data.is_empty())
-        memcpy(shared_buffer->data(), data.characters_without_null_termination(), data.length() + 1);
+        memcpy(shared_buffer->data(), data.data(), data.size() + 1);
     else
         ((u8*)shared_buffer->data())[0] = '\0';
     shared_buffer->seal();
     shared_buffer->share_with(connection().server_pid());
 
-    connection().send_sync<Messages::ClipboardServer::SetClipboardData>(shared_buffer->shbuf_id(), data.length(), type);
+    connection().send_sync<Messages::ClipboardServer::SetClipboardData>(shared_buffer->shbuf_id(), data.size(), type);
 }
 
 void ClipboardServerConnection::handle(const Messages::ClipboardClient::ClipboardDataChanged& message)

Libraries/LibGUI/Clipboard.h

@@ -36,18 +36,23 @@ class Clipboard {
 public:
     static Clipboard& the();
 
-    String data() const { return data_and_type().data; }
-    String type() const { return data_and_type().type; }
-    void set_data(const StringView&, const String& data_type = "text/plain");
+    ByteBuffer data() const { return data_and_type().data; }
+    String mime_type() const { return data_and_type().mime_type; }
+    void set_data(ReadonlyBytes, const String& mime_type = "text/plain");
+
+    void set_plain_text(const String& text)
+    {
+        set_data(text.bytes());
+    }
 
     struct DataAndType {
-        String data;
-        String type;
+        ByteBuffer data;
+        String mime_type;
     };
 
     DataAndType data_and_type() const;
 
-    Function<void(const String& data_type)> on_change;
+    Function<void(const String& mime_type)> on_change;
 
     static void initialize(Badge<Application>);
 

Libraries/LibGUI/TextEditor.cpp

@@ -1300,7 +1300,7 @@ void TextEditor::cut()
         return;
     auto selected_text = this->selected_text();
     printf("Cut: \"%s\"\n", selected_text.characters());
-    Clipboard::the().set_data(selected_text);
+    Clipboard::the().set_plain_text(selected_text);
     delete_selection();
 }
 
@@ -1308,7 +1308,7 @@ void TextEditor::copy()
 {
     auto selected_text = this->selected_text();
     printf("Copy: \"%s\"\n", selected_text.characters());
-    Clipboard::the().set_data(selected_text);
+    Clipboard::the().set_plain_text(selected_text);
 }
 
 void TextEditor::paste()
@@ -1317,7 +1317,7 @@ void TextEditor::paste()
         return;
 
     auto paste_text = Clipboard::the().data();
-    printf("Paste: \"%s\"\n", paste_text.characters());
+    printf("Paste: \"%s\"\n", String::copy(paste_text).characters());
 
     TemporaryChange change(m_automatic_indentation_enabled, false);
     insert_at_cursor_or_replace_selection(paste_text);

Libraries/LibVT/TerminalWidget.cpp

@@ -550,7 +550,7 @@ void TerminalWidget::paste()
     auto text = GUI::Clipboard::the().data();
     if (text.is_empty())
         return;
-    int nwritten = write(m_ptm_fd, text.characters(), text.length());
+    int nwritten = write(m_ptm_fd, text.data(), text.size());
     if (nwritten < 0) {
         perror("write");
         ASSERT_NOT_REACHED();
@@ -560,7 +560,7 @@ void TerminalWidget::paste()
 void TerminalWidget::copy()
 {
     if (has_selection())
-        GUI::Clipboard::the().set_data(selected_text());
+        GUI::Clipboard::the().set_plain_text(selected_text());
 }
 
 void TerminalWidget::mouseup_event(GUI::MouseEvent& event)
@@ -829,7 +829,7 @@ void TerminalWidget::context_menu_event(GUI::ContextMenuEvent& event)
             m_context_menu_for_hyperlink->add_action(action);
         }
         m_context_menu_for_hyperlink->add_action(GUI::Action::create("Copy URL", [this](auto&) {
-            GUI::Clipboard::the().set_data(m_context_menu_href);
+            GUI::Clipboard::the().set_plain_text(m_context_menu_href);
         }));
         m_context_menu_for_hyperlink->add_separator();
         m_context_menu_for_hyperlink->add_action(copy_action());

Libraries/LibWeb/InProcessWebView.cpp

@@ -66,7 +66,7 @@ InProcessWebView::InProcessWebView()
     set_background_role(ColorRole::Base);
 
     m_copy_action = GUI::CommonActions::make_copy_action([this](auto&) {
-        GUI::Clipboard::the().set_data(selected_text(), "text/plain");
+        GUI::Clipboard::the().set_plain_text(selected_text());
     });
 
     m_select_all_action = GUI::CommonActions::make_select_all_action([this](auto&) {