Mojo C++ bindings: support mapping mojo string to WTF::String.

mojo/public/cpp/bindings/tests/wtf_types_unittest.cc

Index: mojo/public/cpp/bindings/tests/wtf_types_unittest.cc
diff --git a/mojo/public/cpp/bindings/tests/wtf_types_unittest.cc b/mojo/public/cpp/bindings/tests/wtf_types_unittest.cc
new file mode 100644
index 0000000000000000000000000000000000000000..65ca93063725fbb79680b5d35b1c02a67ce0ec60
--- /dev/null
+++ b/mojo/public/cpp/bindings/tests/wtf_types_unittest.cc
@@ -0,0 +1,72 @@
+// Copyright 2016 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 "base/message_loop/message_loop.h"
+#include "base/run_loop.h"
+#include "mojo/public/cpp/bindings/binding.h"
+#include "mojo/public/interfaces/bindings/tests/test_wtf_types.mojom-wtf.h"
+#include "mojo/public/interfaces/bindings/tests/test_wtf_types.mojom.h"
+#include "testing/gtest/include/gtest/gtest.h"
+#include "third_party/WebKit/Source/wtf/Partitions.h"
+
+namespace mojo {
+namespace test {
+namespace {
+
+class TestWTFImpl : public TestWTF {
+ public:
+  explicit TestWTFImpl(TestWTFRequest request)
+      : binding_(this, std::move(request)) {}
+
+  // mojo::test::TestWTF implementation:
+  void EchoString(const String& str,
+                  const EchoStringCallback& callback) override {
+    callback.Run(str);
+  }
+
+ private:
+  Binding<TestWTF> binding_;
+};
+
+class WTFTypesTest : public testing::Test {
+ public:
+  WTFTypesTest() {}
+
+ private:
+  // testing::Test overrides:
+  void SetUp() override { WTF::Partitions::initialize(nullptr); }
+
+  base::MessageLoop loop_;
+};
+
+}  // namespace
+
+TEST_F(WTFTypesTest, SendWTFString) {
+  wtf::TestWTFPtr ptr;
+  TestWTFImpl impl(GetProxy(&ptr));
+
+  WTF::String strs[3];
+  // strs[0] is null.
+  // strs[1] is empty.
+  strs[1] = "";
+  strs[2] = "hello world";
+
+  for (size_t i = 0; i < 3; ++i) {
+    base::RunLoop loop;
+    // Test that a WTF::String is unchanged after the following conversion:
+    //   - serialized;
+    //   - deserialized as mojo::String;
+    //   - serialized;
+    //   - deserialized as WTF::String.
+    ptr->EchoString(strs[i],
+                    [&loop, &strs, &i](const WTF::String& str) {
+                      EXPECT_EQ(strs[i], str);
+                      loop.Quit();
+                    });
+    loop.Run();
+  }
+}
+
+}  // namespace test
+}  // namespace mojo