Support partial window

[bwikbs]

Preparation work for #94

• Now it is possible to create a partial app instead of a full screen as follows:

  Ecore_Wl2_Display* ecore_wl2_display_ = nullptr;
  ecore_wl2_init();
  ecore_wl2_display_ = ecore_wl2_display_connect(nullptr);
  ecore_wl2_sync();
  Ecore_Wl2_Window* ecore_wl2_window_ =
      ecore_wl2_window_new(ecore_wl2_display_, nullptr, 100, 100, 500, 600);
  ecore_wl2_window_type_set(ecore_wl2_window_,
                            ECORE_WL2_WINDOW_TYPE_TOPLEVEL);
  ecore_wl2_window_alpha_set(ecore_wl2_window_, false);
  ecore_wl2_window_position_set(ecore_wl2_window_, 0, 0);
  ecore_wl2_window_aux_hint_add(ecore_wl2_window_, 0,
                                "wm.policy.win.user.geometry", "1");
  
  FlutterDesktopEngineProperties engine_prop = {};
  engine_prop.assets_path = assets_path.c_str();
  engine_prop.icu_data_path = icu_data_path.c_str();
  engine_prop.aot_library_path = aot_lib_path.c_str();
  engine_prop.switches = switches.data();
  engine_prop.switches_count = switches.size();
  engine_prop.custom_win = ecore_wl2_window_;

[bbrto21]

After #90, we use Chromium style

[bwikbs]

Thanks for your tip.

[xuelian-bai]

I don't know about this scenario, but I'm curious what's the reason to create the window outside embedder?

[bwikbs]

Preparation work for #94

Considering various situations, multi-screen support in Flutter is still in early stage. So.. using multiple windows and FlutterEngineGroup(https://flutter.dev/docs/development/add-to-app/multiple-flutters) Is being considered as an alternative.

[swift-kim]

Considering various situations, multi-screen support in Flutter is still in early stage.

Could you share your findings on this, why you're using this approach (creating a window in the app side), and what you're eventually going to implement (overall design) in #94 as an issue comment (not here)? I don't understand how this change is even related to multi-window support so far.

[bwikbs]

First of all, I'm sorry that there wasn't much explanation.
What I'm trying to do is reorganized and shared in the linked issue.(#94)

[xuelian-bai]

I checked the android sample, it is showing sample of enginegroup, which share resources when multiple engines exist, but I still don't understand why create a window in app, instead of using the window inside embedder.

[swift-kim]

Could we move the discussion to #94? 🙂

[bwikbs]

Go on #114