Worked around some quirky Linux file system issues. Namely

the Chromebooks share their file system to Linux using the 9p file
system, which does not support setting file ownership. Newly PrusaSlicer
will detect platform and it will not panick if copy_file() cannot set
file ownership after copying. It just logs the incident, and on
chromebooks the loglevel for that incident is "Info", not "Error".

Adjusted the full screen mode to contain menu bar.
Moved Platform.cpp/hpp to libslic3r

src/slic3r/GUI/GUI_Init.cpp

@@ -9,7 +9,6 @@
 #include "slic3r/GUI/format.hpp"
 #include "slic3r/GUI/MainFrame.hpp"
 #include "slic3r/GUI/Plater.hpp"
-#include "slic3r/Utils/Platform.hpp"
 
 // To show a message box if GUI initialization ends up with an exception thrown.
 #include <wx/msgdlg.h>
@@ -37,8 +36,6 @@ int GUI_Run(GUI_InitParams &params)
     signal(SIGCHLD, SIG_DFL);
 #endif // __APPLE__
 
-    detect_platform();
-
     try {
         GUI::GUI_App* gui = new GUI::GUI_App(params.start_as_gcodeviewer ? GUI::GUI_App::EAppMode::GCodeViewer : GUI::GUI_App::EAppMode::Editor);
         if (gui->get_app_mode() != GUI::GUI_App::EAppMode::GCodeViewer) {

src/slic3r/GUI/MainFrame.cpp

@@ -1218,8 +1218,10 @@ void MainFrame::init_menubar_as_editor()
             [this](wxCommandEvent&) { m_plater->collapse_sidebar(!m_plater->is_sidebar_collapsed()); }, this,
             []() { return true; }, [this]() { return m_plater->is_sidebar_collapsed(); }, this);
         append_menu_check_item(viewMenu, wxID_ANY, _L("&Full screen") + "\t" + "F11", _L("Full screen"),
-            [this](wxCommandEvent&) { this->ShowFullScreen(!this->IsFullScreen()); }, this,
-            []() { return true; }, [this]() { return this->IsFullScreen(); }, this);
+            [this](wxCommandEvent&) { this->ShowFullScreen(!this->IsFullScreen(), 
+                // wxFULLSCREEN_ALL: wxFULLSCREEN_NOMENUBAR | wxFULLSCREEN_NOTOOLBAR | wxFULLSCREEN_NOSTATUSBAR | wxFULLSCREEN_NOBORDER | wxFULLSCREEN_NOCAPTION
+                wxFULLSCREEN_NOSTATUSBAR | wxFULLSCREEN_NOBORDER | wxFULLSCREEN_NOCAPTION); }, 
+            this, []() { return true; }, [this]() { return this->IsFullScreen(); }, this);
     }
 
     // Help menu

src/slic3r/GUI/OpenGLManager.cpp

@@ -4,7 +4,8 @@
 #include "GUI.hpp"
 #include "I18N.hpp"
 #include "3DScene.hpp"
-#include "slic3r/Utils/Platform.hpp"
+
+#include "libslic3r/Platform.hpp"
 
 #include <GL/glew.h>
 
@@ -324,7 +325,7 @@ void OpenGLManager::detect_multisample(int* attribList)
         enable_multisample &&
         // Disable multi-sampling on ChromeOS, as the OpenGL virtualization swaps Red/Blue channels with multi-sampling enabled,
         // at least on some platforms.
-        (platform() != Platform::Linux || platform_flavor() != PlatformFlavor::LinuxOnChromium) && 
+        platform_flavor() != PlatformFlavor::LinuxOnChromium &&
         wxGLCanvas::IsDisplaySupported(attribList)
         ? EMultisampleState::Enabled : EMultisampleState::Disabled;
     // Alternative method: it was working on previous version of wxWidgets but not with the latest, at least on Windows

src/slic3r/GUI/Plater.cpp

@@ -76,7 +76,6 @@
 #include "../Utils/FixModelByWin10.hpp"
 #include "../Utils/UndoRedo.hpp"
 #include "../Utils/PresetUpdater.hpp"
-#include "../Utils/Platform.hpp"
 #include "../Utils/Process.hpp"
 #include "RemovableDriveManager.hpp"
 #include "InstanceCheck.hpp"
@@ -89,7 +88,9 @@
 
 #include <wx/glcanvas.h>    // Needs to be last because reasons :-/
 #include "WipeTowerDialog.hpp"
+
 #include "libslic3r/CustomGCode.hpp"
+#include "libslic3r/Platform.hpp"
 
 using boost::optional;
 namespace fs = boost::filesystem;
@@ -3660,7 +3661,7 @@ void Plater::priv::on_process_completed(SlicingProcessCompletedEvent &evt)
             show_action_buttons(false);
             notification_manager->push_exporting_finished_notification(last_output_path, last_output_dir_path,
                 // Don't offer the "Eject" button on ChromeOS, the Linux side has no control over it.
-                platform() != Platform::Linux || platform_flavor() != PlatformFlavor::LinuxOnChromium);
+                platform_flavor() != PlatformFlavor::LinuxOnChromium);
             wxGetApp().removable_drive_manager()->set_exporting_finished(true);
         }else if (exporting_status == ExportingStatus::EXPORTING_TO_LOCAL && !has_error)
             notification_manager->push_exporting_finished_notification(last_output_path, last_output_dir_path, false);

src/slic3r/GUI/PresetHints.cpp

@@ -139,7 +139,6 @@ std::string PresetHints::maximum_volumetric_flow_description(const PresetBundle
 		const ConfigOptionFloatOrPercent *first_layer_extrusion_width_ptr = (first_layer && first_layer_extrusion_width.value > 0) ?
 			&first_layer_extrusion_width : nullptr;
         const float                       lh  = float(first_layer ? first_layer_height : layer_height);
-        const float                       bfr = bridging ? bridge_flow_ratio : 0.f;
         double                            max_flow = 0.;
         std::string                       max_flow_extrusion_type;
         auto                              limit_by_first_layer_speed = [&first_layer_speed, first_layer](double speed_normal, double speed_max) {

src/slic3r/GUI/RemovableDriveManager.cpp

@@ -1,5 +1,5 @@
 #include "RemovableDriveManager.hpp"
-#include "slic3r/Utils/Platform.hpp"
+#include "libslic3r/Platform.hpp"
 #include <libslic3r/libslic3r.h>
 
 #include <boost/nowide/convert.hpp>
@@ -232,7 +232,7 @@ std::vector<DriveData> RemovableDriveManager::search_for_removable_drives() cons
 
 #else
 
-   	if (platform() == Platform::Linux && platform_flavor() == PlatformFlavor::LinuxOnChromium) {
+   	if (platform_flavor() == PlatformFlavor::LinuxOnChromium) {
 	    // ChromeOS specific: search /mnt/chromeos/removable/* folder
 		search_for_drives_internal::search_path("/mnt/chromeos/removable/*", "/mnt/chromeos/removable", current_drives);
    	} else {
@@ -452,7 +452,7 @@ RemovableDriveManager::RemovableDrivesStatus RemovableDriveManager::status()
 		tbb::mutex::scoped_lock lock(m_drives_mutex);
 		out.has_eject = 
 			// Cannot control eject on Chromium.
-			(platform() != Platform::Linux || platform_flavor() != PlatformFlavor::LinuxOnChromium) &&
+			platform_flavor() != PlatformFlavor::LinuxOnChromium &&
 			this->find_last_save_path_drive_data() != m_current_drives.end();
 		out.has_removable_drives = ! m_current_drives.empty();
 	}