Update flutter_windows_view.cc

Add more context around resizing.

Author: iskakaushik

shell/platform/windows/flutter_windows_view.cc

@@ -9,6 +9,11 @@
 namespace flutter {
 
 /// Returns true if the surface will be updated as part of the resize process.
+///
+/// This is called on window resize to determine if the platform thread needs
+/// to be blocked until the frame with the right size has been rendered. It should
+/// be kept in-sync with how the engine deals with a new surface request as seen in
+/// `CreateOrUpdateSurface` in `GPUSurfaceGL`.
 static bool SurfaceWillUpdate(size_t cur_width,
                               size_t cur_height,
                               size_t target_width,