flutter: Rewrite flutter frontend to use only the KDDW layouting

This greatly simplifies the flutter port. KDDW now only drives
the layouting and doesn't abstract tabs, windows and DnD anymore,
which will now be done in Dart.

The amount of over-engineered abstractions in C++ was causing it to be
a pain to even do simple bug fixes. The code is now very clean in dart,
without needing to go back and forth to C++ land for every mouse click.

Allows to get rid of dartagnan which broke whenever shiboken or LLVM
was updated.

Allows to get rid of qcoro co-routines as tests are no longer driven
by C++, no need to mix 2 event loops.

The state of the port is still dependent on flutter supporting
multi-window, but we're now in a position to move faster, as tons
of tech debt have been removed.

.github/workflows/flutter-dev.yml

@@ -0,0 +1,67 @@
+# SPDX-FileCopyrightText: 2023 Klarälvdalens Datakonsult AB, a KDAB Group company <[email protected]>
+#
+# SPDX-License-Identifier: GPL-2.0-only OR GPL-3.0-only
+
+# Builds the flutter frontend
+# Doesn't run tests yet though
+
+name: Flutter-dev
+
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+    branches:
+      - main
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: true
+      matrix:
+        preset:
+          - name: dev-flutter
+            isAOT: false
+            args: []
+          # - name: dev-flutter-asan
+          #   isAOT: false
+          #   args: ["--asan"]
+          # - name: dev-flutter-aot
+          #   isAOT: true
+          #   args: ["--aot"]
+          # - name: dev-flutter-aot-asan
+          #   isAOT: true
+          #   args: ["--aot", "--asan"]
+
+    steps:
+      - name: Checkout sources
+        uses: actions/checkout@v4
+
+      - name: Install dependencies on Ubuntu
+        run: |
+          sudo apt update -qq
+          sudo apt install libgtk-3-dev libglib2.0-dev ninja-build libspdlog-dev lld xvfb -y
+
+      - uses: subosito/flutter-action@v2
+        with:
+          flutter-version: "3.x"
+          channel: "stable"
+
+      - name: Configure project ${{ matrix.preset.name }}
+        run: cmake -S . -B ./build-${{ matrix.preset.name }} --preset ${{ matrix.preset.name }}
+
+      - name: Build Project ${{ matrix.preset.name }}
+        run: cmake --build ./build-${{ matrix.preset.name }}
+
+      - name: Build the example
+        run: |
+          cd examples/flutter
+          flutter build linux
+
+      - name: Run tests
+        run: |
+          cd src/flutter/dart
+          flutter pub get
+          xvfb-run flutter test

.github/workflows/flutter-pub-update.yml_ → .github/workflows/flutter-pub-update.yml

@@ -8,14 +8,12 @@ name: (Scheduled) Runs flutter pub upgrade
 
 on:
   schedule:
-  - cron: '0 0 1 * *' # monthly
+    - cron: "0 0 1 * *" # monthly
   workflow_dispatch:
 
 jobs:
   build:
     runs-on: ubuntu-latest
-    strategy:
-      fail-fast: true
 
     steps:
       - name: Checkout sources
@@ -31,32 +29,17 @@ jobs:
       - name: Install Flutter SDK
         uses: subosito/flutter-action@v2
         with:
-          flutter-version: '3.19.6'
-          channel: 'stable'
+          flutter-version: "3.x"
+          channel: "stable"
 
       - name: Setup git author name
         uses: fregante/setup-git-user@v2
 
-      - name: pub upgrade on flutter_tests_embedder
-        run: |
-          cd tests/flutter_tests_embedder/
-          flutter pub upgrade
-
-      - name: pub upgrade on flutter_tests_embedder
-        run: |
-          cd tests/flutter_tests_embedder/
-          flutter pub upgrade --major-versions
-
       - name: pub upgrade on examples
         run: |
           cd examples/flutter
           flutter pub upgrade --major-versions
 
-      - name: pub upgrade on src/flutter
-        run: |
-          cd src/flutter
-          flutter pub upgrade --major-versions
-
       - name: pub upgrade on src/flutter/dart
         run: |
           cd src/flutter/dart

.github/workflows/flutter-rel.yml_ → .github/workflows/flutter-rel.yml

@@ -37,13 +37,6 @@ jobs:
             flutter_os: "macos"
 
     steps:
-      - name: Install Qt
-        if: ${{ matrix.preset.name == 'release-flutter-qwindow' }}
-        uses: jurplel/install-qt-action@v3
-        with:
-          version: 6.7.2
-          cache: true
-
       - name: Checkout sources
         uses: actions/checkout@v4
 
@@ -58,8 +51,8 @@ jobs:
 
       - uses: subosito/flutter-action@v2
         with:
-          flutter-version: '3.24.0'
-          channel: 'stable'
+          flutter-version: "3.x"
+          channel: "stable"
 
       - name: MSVC into PATH
         if: ${{ runner.os == 'Windows' }}

.gitignore

@@ -113,3 +113,4 @@ kddockwidgets_example.iml
 
 /docs/book/book/
 /book/
+/src/flutter/dart/build/