fix(texture): guard render-thread teardown against engine shutdown

The render-thread teardown task posted by UnregisterTexture() captures a raw
renderer pointer. If the engine shuts down before the task runs,
PostRenderThreadTask() runs it inline and the renderer may already be
destroyed, so gl_renderer->OnMakeCurrent() could touch a dangling GL
context/renderer.

Guard the OnMakeCurrent() call with engine->IsRunning(). UnregisterExternalTexture()
stays unconditional: it is null-safe at the embedder boundary (a torn-down
engine handle just yields an error return) and is the registrar's core
teardown step, so guarding it would skip the mandatory unregistration in the
non-running case (and breaks the RegisterUnregisterTexture unit test, whose
engine is never run).

Also reflow the FlutterDesktopTextureRegistrarUnregisterExternalTexture call
to satisfy clang-format.

Author: seungsoo47

flutter/shell/platform/tizen/flutter_tizen.cc

@@ -330,8 +330,8 @@ void FlutterDesktopTextureRegistrarUnregisterExternalTexture(
     int64_t texture_id,
     void (*callback)(void* user_data),
     void* user_data) {
-  TextureRegistrarFromHandle(texture_registrar)->UnregisterTexture(
-      texture_id, callback, user_data);
+  TextureRegistrarFromHandle(texture_registrar)
+      ->UnregisterTexture(texture_id, callback, user_data);
 }
 
 bool FlutterDesktopTextureRegistrarMarkExternalTextureFrameAvailable(

flutter/shell/platform/tizen/flutter_tizen_texture_registrar.cc

@@ -110,7 +110,15 @@ bool FlutterTizenTextureRegistrar::UnregisterTexture(int64_t texture_id,
         // glDeleteTextures in the texture's destructor targets the correct
         // context (the engine does not guarantee a current context when
         // running posted tasks).
-        if (gl_renderer) {
+        //
+        // If the engine has shut down between PostRenderThreadTask() being
+        // called and this task running, PostRenderThreadTask() runs the task
+        // inline and the renderer may already be destroyed, so skip
+        // OnMakeCurrent() to avoid touching a dangling GL context/renderer.
+        // UnregisterExternalTexture() stays unconditional: it is null-safe at
+        // the embedder boundary (a torn-down engine handle just yields an
+        // error) and is the registrar's core teardown step.
+        if (engine->IsRunning() && gl_renderer) {
           gl_renderer->OnMakeCurrent();
         }
         tex.reset();