Remove the unnecessary conversion to wstring when calling file_util::WriteFile.

Also use FilePath in npapi_test_helper.

BUG=24672
TEST=compiled

Review URL: http://codereview.chromium.org/266061
Patch from Thiago Farina <[email protected]>.

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@28856 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/net/base/file_stream_unittest.cc b/net/base/file_stream_unittest.cc
index 76909eb..a7a650f 100644
--- a/net/base/file_stream_unittest.cc
+++ b/net/base/file_stream_unittest.cc
@@ -22,8 +22,7 @@
     PlatformTest::SetUp();
 
     file_util::CreateTemporaryFile(&temp_file_path_);
-    file_util::WriteFile(temp_file_path_.ToWStringHack(),
-                         kTestData, kTestDataSize);
+    file_util::WriteFile(temp_file_path_, kTestData, kTestDataSize);
   }
   virtual void TearDown() {
     file_util::Delete(temp_file_path_, false);