Enable mojo js tests which depend on mojom.js files in gen/.

mojo/common/test/test_utils.h

 // 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.
 
 #ifndef MOJO_COMMON_TEST_TEST_UTILS_H_
 #define MOJO_COMMON_TEST_TEST_UTILS_H_
 
 #include <stddef.h>
 
+#include <string>
+
+#include "base/files/file_path.h"
+
 namespace mojo {
 
 namespace embedder {
 struct PlatformHandle;
 }
 
 namespace test {
 
 // On success, |bytes_written| is updated to the number of bytes written;
 // otherwise it is untouched.
@@ skipping 11 matching lines @@
 
 // If the read is done successfully or would block, the function returns true
 // and updates |bytes_read| to the number of bytes read (0 if the read would
 // block); otherwise it returns false and leaves |bytes_read| untouched.
 // |handle| must already be in non-blocking mode.
 bool NonBlockingRead(const embedder::PlatformHandle& handle,
                      void* buffer,
                      size_t buffer_size,
                      size_t* bytes_read);
 
+// Returns the path to the mojom js bindings file.
+base::FilePath GetFilePathForJSResource(const std::string& path);
+
 }  // namespace test
 }  // namespace mojo
 
 #endif  // MOJO_COMMON_TEST_TEST_UTILS_H_