void ShowMyDialog(...);
//chrome/browser/ui/views/my_dialog_views.cc:
void ShowMyDialog(...) { ... }
//chrome/browser/ui/android/my_dialog_android.cc:
void ShowMyDialog(...) { ... }
Because “Chromium UI” is such a large surface area, do not add new files directly to this directory; instead, add subdirectories with more specific OWNERS and place new features and files in them. Cleanup of existing scattered files is also welcome.