Codesearach xrefs are incorrect for RequiresCompositingForScrollableFrame:

Declaration:
https://cs.chromium.org/chromium/src/third_party/WebKit/Source/core/layout/compositing/CompositingReasonFinder.h?type=cs&q=RequiresCompositingForScrollableFrame&l=38

Definition:
https://cs.chromium.org/chromium/src/third_party/WebKit/Source/core/layout/compositing/CompositingReasonFinder.cpp?type=cs&l=57

Should be called from:
https://cs.chromium.org/chromium/src/third_party/WebKit/Source/core/layout/compositing/PaintLayerCompositor.cpp?type=cs&l=140

I checked each of the blames above and this doesn't seem to be a recent change that might stem from xrefs lagging behind.