Add RestartEngine API to handle cold-restart scenario

Signed-off-by: MuHong Byun <mh.byun@samsung.com>

Author: bwikbs

shell/platform/tizen/channels/platform_view_channel.cc

@@ -80,6 +80,10 @@ void PlatformViewChannel::ClearViewFactories() {
   view_factories_.clear();
 }
 
+void PlatformViewChannel::PreEngineRestart() {
+  ClearViewInstances();
+}
+
 void PlatformViewChannel::SendKeyEvent(Ecore_Event_Key* key, bool is_down) {
   auto instances = ViewInstances();
   auto it = instances.find(CurrentFocusedViewId());

shell/platform/tizen/channels/platform_view_channel.h

@@ -38,6 +38,8 @@ class PlatformViewChannel {
   void DispatchCompositionUpdateEvent(const std::string& key);
   void DispatchCompositionEndEvent(const std::string& key);
 
+  void PreEngineRestart();
+
  private:
   void HandleMethodCall(
       const flutter::MethodCall<flutter::EncodableValue>& call,

shell/platform/tizen/flutter_tizen_engine.cc

@@ -194,6 +194,12 @@ bool FlutterTizenEngine::RunEngine(
         auto engine = reinterpret_cast<FlutterTizenEngine*>(user_data);
         auto message = engine->ConvertToDesktopMessage(*engine_message);
         engine->message_dispatcher->HandleMessage(message);
+
+        // Workarounds for handling engine restarts. Needs to be replaced by
+        // PlatformView::OnPreEngineRestart.
+        if (strncmp(message.channel, "flutter/isolate", 15) == 0) {
+          engine->RestartEngine();
+        }
       };
   args.custom_task_runners = &custom_task_runners;
 #ifndef TIZEN_RENDERER_EVAS_GL
@@ -270,6 +276,13 @@ bool FlutterTizenEngine::StopEngine() {
   return false;
 }
 
+void FlutterTizenEngine::RestartEngine() {
+  // Need to reset native resource.
+  if (platform_view_channel) {
+    platform_view_channel->PreEngineRestart();
+  }
+}
+
 FlutterDesktopPluginRegistrarRef FlutterTizenEngine::GetPluginRegistrar() {
   return plugin_registrar_.get();
 }

shell/platform/tizen/flutter_tizen_engine.h

@@ -70,6 +70,8 @@ class FlutterTizenEngine : public TizenRenderer::Delegate {
   bool RunEngine(const FlutterDesktopEngineProperties& engine_properties);
   bool StopEngine();
 
+  void RestartEngine();
+
   // Returns the currently configured Plugin Registrar.
   FlutterDesktopPluginRegistrarRef GetPluginRegistrar();