As mentioned in this comment:

https://bugs.chromium.org/p/chromium/issues/detail?id=624274#c22

chrome.exe and chrome_child.dll have an extra 50 KB of .rsrc data which can be removed once we have committed to the gn switch. This comment from ui\resources\BUILD.gn explains why can be done once GYP is gone.

# TODO(GYP_GONE) when GYP is gone, this line should be deleted, and the grit
# file updated to no longer list this as an output. We use resource bundles
# rather than .rc files, but the GYP build still expects this file to
# exist.
"ui_unscaled_resources.rc",