40         : fHead(std::move(op)), fTail(fHead.get()) {  in List()
48     fHead = std::move(that.fHead);  in operator =()
56     SkASSERT(fHead);  in popHead()
57     auto temp = fHead->cutChain();  in popHead()
58     std::swap(temp, fHead);  in popHead()
59     if (!fHead) {  in popHead()
70     SkASSERT(head == fHead.get());  in removeOp()
74         SkASSERT(op == fHead.get());  in removeOp()
92     if (fHead) {  in pushHead()
93         op->chainConcat(std::move(fHead));  in pushHead()
94         fHead = std::move(op);  in pushHead()
96         fHead = std::move(op);  in pushHead()
97         fTail = fHead.get();  in pushHead()
109     if (fHead) {  in validate()
111         fHead->validateChain(fTail);  in validate()