Add U2F request state machines

device/u2f/BUILD.gn

Index: device/u2f/BUILD.gn
diff --git a/device/u2f/BUILD.gn b/device/u2f/BUILD.gn
index 91fd6a26afed8b5f43413c876e0420b31af17afb..0fcfe4b126856721056d1e5c68316e82183c1894 100644
--- a/device/u2f/BUILD.gn
+++ b/device/u2f/BUILD.gn
@@ -19,6 +19,13 @@ source_set("u2f") {
     "u2f_message.h",
     "u2f_packet.cc",
     "u2f_packet.h",
+    "u2f_register.cc",
+    "u2f_register.h",
+    "u2f_request.cc",
+    "u2f_request.h",
+    "u2f_return_code.h",
+    "u2f_sign.cc",
+    "u2f_sign.h",
   ]
 
   deps = [
@@ -30,6 +37,21 @@ source_set("u2f") {
   ]
 }
 
+source_set("mocks") {
+  testonly = true
+
+  sources = [
+    "mock_u2f_device.cc",
+    "mock_u2f_device.h",
+  ]
+
+  deps = [
+    ":u2f",
+    "//base",
+    "//testing/gmock",
+  ]
+}
+
 fuzzer_test("u2f_apdu_fuzzer") {
   sources = [
     "u2f_apdu_fuzzer.cc",