fix

Author: iskakaushik

shell/gpu/gpu_surface_metal.mm

@@ -92,7 +92,8 @@
 
         canvas->flush();
 
-        return delegate->PresentDrawable(drawable);
+        bool present_result = delegate->PresentDrawable(drawable);
+        return present_result;
       });
 
   return std::make_unique<SurfaceFrame>(std::move(surface), true, submit_callback);

shell/platform/darwin/ios/ios_surface_metal.mm

@@ -82,10 +82,7 @@
   [command_buffer.get() commit];
   [command_buffer.get() waitUntilScheduled];
 
-  fml::scoped_nsprotocol<id<CAMetalDrawable>> drawable_holder(
-      reinterpret_cast<id<CAMetalDrawable>>(drawable));
-  [drawable_holder.get() present];
-
+  [reinterpret_cast<id<CAMetalDrawable>>(drawable) present];
   return true;
 }