Mojo: Add support for InterfacePtr as a struct member

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

Index: mojo/public/cpp/bindings/tests/handle_passing_unittest.cc
diff --git a/mojo/public/cpp/bindings/tests/handle_passing_unittest.cc b/mojo/public/cpp/bindings/tests/handle_passing_unittest.cc
index 99eddf83410615547d2b3be19a7f8437fb4cf792..ab2e47506cc4d7192398be09df6da1bca38022e7 100644
--- a/mojo/public/cpp/bindings/tests/handle_passing_unittest.cc
+++ b/mojo/public/cpp/bindings/tests/handle_passing_unittest.cc
@@ -26,6 +26,24 @@ class StringRecorder {
   std::string* buf_;
 };
 
+class ImportedInterfaceImpl
+    : public InterfaceImpl<imported::ImportedInterface> {
+ public:
+  virtual void OnConnectionError() MOJO_OVERRIDE {
+    delete this;
+  }
+
+  virtual void DoSomething() MOJO_OVERRIDE {
+    do_something_count_++;
+  }
+
+  static int do_something_count() { return do_something_count_; }
+
+ private:
+  static int do_something_count_;
+};
+int ImportedInterfaceImpl::do_something_count_ = 0;
+
 class SampleNamedObjectImpl : public InterfaceImpl<sample::NamedObject> {
  public:
   virtual void OnConnectionError() MOJO_OVERRIDE {
@@ -75,6 +93,9 @@ class SampleFactoryImpl : public InterfaceImpl<sample::Factory> {
     response->x = 2;
     response->pipe = pipe0.Pass();
     client()->DidStuff(response.Pass(), text1);
+
+    if (request->obj.get())
+      request->obj->DoSomething();
   }
 
   virtual void DoStuff2(ScopedDataPipeConsumerHandle pipe) MOJO_OVERRIDE {
@@ -194,16 +215,22 @@ TEST_F(HandlePassingTest, Basic) {
   MessagePipe pipe1;
   EXPECT_TRUE(WriteTextMessage(pipe1.handle1.get(), kText2));
 
+  imported::ImportedInterfacePtr imported;
+  BindToProxy(new ImportedInterfaceImpl(), &imported);
+
   sample::RequestPtr request(sample::Request::New());
   request->x = 1;
   request->pipe = pipe1.handle0.Pass();
+  request->obj = imported.Pass();
   factory->DoStuff(request.Pass(), pipe0.handle0.Pass());
 
   EXPECT_FALSE(factory_client.got_response());
+  int count_before = ImportedInterfaceImpl::do_something_count();
 
   PumpMessages();
 
   EXPECT_TRUE(factory_client.got_response());
+  EXPECT_EQ(1, ImportedInterfaceImpl::do_something_count() - count_before);
 }
 
 TEST_F(HandlePassingTest, PassInvalid) {