Remove more wstrings in webkit/tools/test_shell.

webkit/tools/test_shell/image_decoder_unittest.cc

Index: webkit/tools/test_shell/image_decoder_unittest.cc
diff --git a/webkit/tools/test_shell/image_decoder_unittest.cc b/webkit/tools/test_shell/image_decoder_unittest.cc
index 82b3bb7ee8faac0821db8fdbd44b3b0abe049515..a2eb22a286076a6fc1d862ca8fe234f39d74016b 100644
--- a/webkit/tools/test_shell/image_decoder_unittest.cc
+++ b/webkit/tools/test_shell/image_decoder_unittest.cc
@@ -50,7 +50,7 @@ FilePath GetMD5SumPath(const FilePath& path) {
 }
 
 #if defined(CALCULATE_MD5_SUMS)
-void SaveMD5Sum(const std::wstring& path, const WebKit::WebImage& web_image) {
+void SaveMD5Sum(const FilePath& path, const WebKit::WebImage& web_image) {
   // Calculate MD5 sum.
   base::MD5Digest digest;
   web_image.getSkBitmap().lockPixels();
@@ -209,7 +209,7 @@ void  ImageDecoderTest::TestWebKitImageDecoder(const FilePath& image_path,
   // image dats to the size is returned.
   WebKit::WebSize size(decoder->getImage(desired_frame_index).size());
   const WebKit::WebImage& image = WebKit::WebImage::fromData(data, size);
-  SaveMD5Sum(md5_sum_path.value(), image);
+  SaveMD5Sum(md5_sum_path, image);
 #else
   VerifyImage(*decoder, image_path, md5_sum_path, desired_frame_index);
 #endif