Mojo: Move public C system header files to mojo/public/c/system/.

mojo/public/tests/system/macros_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.
 
 // This file consists of "positive" tests, i.e., those verifying that things
 // work (without compile errors, or even warnings if warnings are treated as
 // errors).
 // TODO(vtl): Fix no-compile tests (which are all disabled; crbug.com/105388)
 // and write some "negative" tests.
 
-#include "mojo/public/system/macros.h"
+#include "mojo/public/c/system/macros.h"
 
 #include <assert.h>
 #include <stdint.h>
 #include <stdlib.h>
 
-#include "mojo/public/system/macros.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace mojo {
 namespace {
 
 TEST(MacrosTest, AllowUnused) {
   // Test that no warning/error is issued even though |x| is unused.
   int x MOJO_ALLOW_UNUSED = 123;
 }
 
@@ skipping 112 matching lines @@
   EXPECT_FALSE(y.is_set());
   EXPECT_TRUE(z.is_set());
   EXPECT_EQ(123, z.value());
   z = z.Pass();
   EXPECT_TRUE(z.is_set());
   EXPECT_EQ(123, z.value());
 }
 
 }  // namespace
 }  // namespace mojo