Constructor and call argument forwarding for SkFunction.

tests/FunctionTest.cpp

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkFunction.h"
 #include "Test.h"
 
@@ skipping 13 matching lines @@
     // all into an SkFunction equally well.
     test_add_five(r, SkFunction<int(int)>(&add_five));
     test_add_five(r, SkFunction<int(int)>(AddFive()));
     test_add_five(r, SkFunction<int(int)>([](int x) { return x + 5; }));
 
     // AddFive and the lambda above are both small enough to test small-object optimization.
     // Now test a lambda that's much too large for the small-object optimization.
     int a = 1, b = 1, c = 1, d = 1, e = 1;
     test_add_five(r, SkFunction<int(int)>([&](int x) { return x + a + b + c + d + e; }));
 }
+
+DEF_TEST(Function_forwarding, r) {
+    class MoveOnlyAdd5 : SkNoncopyable {
+    public:
+        MoveOnlyAdd5() {}
+        MoveOnlyAdd5(MoveOnlyAdd5&&) {}
+        MoveOnlyAdd5& operator=(MoveOnlyAdd5&&) { return *this; }
+
+        int operator()(int x) { return x + 5; }
+    };
+
+    // Makes sure we forward the functor when constructing SkFunction.
+    test_add_five(r, SkFunction<int(int)>(MoveOnlyAdd5()));
+
+    // Makes sure we forward arguments when calling SkFunction.
+    SkFunction<int(int, MoveOnlyAdd5&&, int)> b([](int x, MoveOnlyAdd5&& f, int y) {
+        return x * f(y);
+    });
+    REPORTER_ASSERT(r, b(2, MoveOnlyAdd5(), 4) == 18);
+}