Add Blink use counter for partitioned cookies

This CL adds a use counter for partitioned cookies which propagates to
Blink during the Origin Trial.

It also adds a PartitionedCookies WebFeature enum entry.

Bug: 1225444,1296161
Change-Id: I86380512fd39db8725971d3a256783369c3ec2ab
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3502230
Reviewed-by: Chris Fredrickson <cfredric@chromium.org>
Reviewed-by: Robert Kroeger <rjkroege@chromium.org>
Commit-Queue: Dylan Cutler <dylancutler@google.com>
Cr-Commit-Position: refs/heads/main@{#977709}
NOKEYCHECK=True
GitOrigin-RevId: 8d5f8911454a8560225ffd98e32a2777b942b481

blink/public/mojom/web_feature/web_feature.mojom

@@ -3495,6 +3495,7 @@ enum WebFeature {
   kMediaCapabilitiesDecodingInfoWebrtc = 4174,
   kMediaCapabilitiesEncodingInfoWebrtc = 4175,
   kUsbDeviceForget = 4176,
+  kPartitionedCookies = 4177,
 
   // Add new features immediately above this line. Don't change assigned
   // numbers of any item, and don't reuse removed slots.