Add RoutingIDIssuer to ensure the correctness of ID to be routed.

content/browser/renderer_host/routing_id_issuer_unittest.cc

+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "content/browser/renderer_host/routing_id_issuer.h"
+
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace content {
+namespace {
+
+const int kMangler = 5;
+
+class RoutingIDIssuerTest : public testing::Test {};
+
+TEST_F(RoutingIDIssuerTest, IssueNext) {
+  scoped_ptr<RoutingIDIssuer> target =
+      RoutingIDIssuer::CreateWithMangler(kMangler);
+  int id0 = target->IssueNext();
+  int id1 = target->IssueNext();
+  EXPECT_EQ(id0 + 1, id1);
+}
+
+TEST_F(RoutingIDIssuerTest, IsProbablyValid) {
+  scoped_ptr<RoutingIDIssuer> proper =
+      RoutingIDIssuer::CreateWithMangler(kMangler);
+  scoped_ptr<RoutingIDIssuer> foreign =
+      RoutingIDIssuer::CreateWithMangler(kMangler + 1);
+
+  EXPECT_FALSE(proper->IsProbablyValid(kMangler));
+
+  int proper_id = proper->IssueNext();
+  int foreign_id = foreign->IssueNext();
+  EXPECT_TRUE(proper->IsProbablyValid(proper_id));
+  EXPECT_TRUE(foreign->IsProbablyValid(foreign_id));
+  EXPECT_FALSE(proper->IsProbablyValid(foreign_id));
+  EXPECT_FALSE(foreign->IsProbablyValid(proper_id));
+}
+
+}  // namespace
+}  // namespace contnet