Disable default paging in list watches

For 1.8 this will be off by default. In 1.9 it will be on by default.
Add tests and rename some fields to use the `chunking` terminology.

Note that the pager may be used for other things besides chunking.

Kubernetes-commit: 8b571bb63bd8a9a6a37db6046a6ab35d3b047bf4

tools/pager/pager.go

@@ -52,7 +52,8 @@ type ListPager struct {
 }
 
 // New creates a new pager from the provided pager function using the default
-// options.
+// options. It will fall back to a full list if an expiration error is encountered
+// as a last resort.
 func New(fn ListPageFunc) *ListPager {
 	return &ListPager{
 		PageSize:          defaultPageSize,
@@ -61,9 +62,12 @@ func New(fn ListPageFunc) *ListPager {
 	}
 }
 
+// TODO: introduce other types of paging functions - such as those that retrieve from a list
+// of namespaces.
+
 // List returns a single list object, but attempts to retrieve smaller chunks from the
 // server to reduce the impact on the server. If the chunk attempt fails, it will load
-// the full list instead.
+// the full list instead. The Limit field on options, if unset, will default to the page size.
 func (p *ListPager) List(ctx context.Context, options metav1.ListOptions) (runtime.Object, error) {
 	if options.Limit == 0 {
 		options.Limit = p.PageSize