Use explicit WebString <-> string16 conversion methods in storage API files

content/child/webfileutilities_impl.cc

Index: content/child/webfileutilities_impl.cc
diff --git a/content/child/webfileutilities_impl.cc b/content/child/webfileutilities_impl.cc
index 268ed0910607d3ca5f21787238c13ab5ee7b0e8f..64ee0b6bea47046c4ce0080b977630b77ebec6de 100644
--- a/content/child/webfileutilities_impl.cc
+++ b/content/child/webfileutilities_impl.cc
@@ -43,11 +43,12 @@ bool WebFileUtilitiesImpl::getFileInfo(const WebString& path,
 }
 
 WebString WebFileUtilitiesImpl::directoryName(const WebString& path) {
-  return blink::WebStringToFilePath(path).DirName().AsUTF16Unsafe();
+  return blink::FilePathToWebString(blink::WebStringToFilePath(path).DirName());
 }
 
 WebString WebFileUtilitiesImpl::baseName(const WebString& path) {
-  return blink::WebStringToFilePath(path).BaseName().AsUTF16Unsafe();
+  return blink::FilePathToWebString(
+      blink::WebStringToFilePath(path).BaseName());
 }
 
 blink::WebURL WebFileUtilitiesImpl::filePathToURL(const WebString& path) {