Add the copresence component.

components/copresence/proto/identity.proto

+syntax = "proto2";
+package copresence;
+option optimize_for = LITE_RUNTIME;
+import "enums.proto";
+message Identity {
+  optional IdentityType type = 1;
+  optional string obfuscated_gaia_id = 2 [deprecated = true];
+  optional string chromecast_id = 3;
+  optional string android_id = 4;
+  optional string chrome_id = 5;
+  optional int64 gaia_id = 6;
+}
+message DeviceIdentity {
+  optional Identity identity = 1;
+  optional DeviceVersion version = 2;
+}
+message DeviceVersion {
+  optional string brand = 1;
+  optional string product = 2;
+  optional string version = 3;
+}